U.S. patent application number 17/151105 was filed with the patent office on 2022-07-21 for contention window adjustment for new radio unlicensed/sidelink.
The applicant listed for this patent is QUALCOMM Incorporated. Invention is credited to Chih-Hao Liu, Jing Sun, Yisheng Xue, Xiaoxia Zhang.
Application Number | 20220232625 17/151105 |
Document ID | / |
Family ID | 1000005386624 |
Filed Date | 2022-07-21 |
United States Patent
Application |
20220232625 |
Kind Code |
A1 |
Liu; Chih-Hao ; et
al. |
July 21, 2022 |
CONTENTION WINDOW ADJUSTMENT FOR NEW RADIO UNLICENSED/SIDELINK
Abstract
Methods, systems, and devices for wireless communications are
described. A transmitting device may perform a first transmission
to one or more receiving devices, the first transmission associated
with a transmission type. The transmitting device may determine a
feedback response for the first transmission based on monitoring
for feedback messages from the one or more receiving devices in
response to the first transmission. The transmitting device may
select a contention window size for performing one or more
subsequent transmissions based at least in part on the feedback
response and the transmission type. The transmitting device may
perform the one or more subsequent transmissions in accordance with
a clear channel assessment procedure using the selected contention
window size.
Inventors: |
Liu; Chih-Hao; (San Diego,
CA) ; Sun; Jing; (San Diego, CA) ; Zhang;
Xiaoxia; (San Diego, CA) ; Xue; Yisheng; (San
Diego, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
QUALCOMM Incorporated |
San Diego |
CA |
US |
|
|
Family ID: |
1000005386624 |
Appl. No.: |
17/151105 |
Filed: |
January 15, 2021 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04W 74/0808
20130101 |
International
Class: |
H04W 74/08 20060101
H04W074/08 |
Claims
1. A method for wireless communication at a transmitting device,
comprising: performing a first transmission to one or more
receiving devices, the first transmission associated with a
transmission type; determining a feedback response for the first
transmission based on monitoring for feedback messages from the one
or more receiving devices in response to the first transmission;
selecting a contention window size for performing one or more
subsequent transmissions based at least in part on the feedback
response and the transmission type; and performing the one or more
subsequent transmissions in accordance with a clear channel
assessment procedure using the selected contention window size.
2. The method of claim 1, wherein the transmission type comprises a
connectionless-based groupcast transmission type, further
comprising: determining that no feedback messages were received
from the one or more receiving devices for the first transmission;
determining that a second transmission was multiplexed with the
first transmission during a same slot, the second transmission
associated with a different transmission type; and selecting, based
at least in part on receiving at least one feedback message for the
second transmission, the contention window size for performing the
one or more subsequent transmissions.
3. The method of claim 1, wherein the transmission type comprises a
connectionless-based groupcast transmission type, further
comprising: determining that no feedback messages were received
from the one or more receiving devices; determining that no second
transmission types were multiplexed with the first transmission
during a same slot; and maintaining, based at least in part on no
feedback messages and no second transmission types being
multiplexed with the first transmission during the same slot, the
contention window size for performing the one or more subsequent
transmissions.
4. The method of claim 1, wherein the transmission type comprises a
connectionless-based groupcast transmission type, further
comprising: determining that at least one negative-acknowledgement
feedback message was received from the one or more receiving
devices; and resetting, based at least in part on the at least one
negative-acknowledgement feedback message, the contention window
size for performing the one or more subsequent transmissions.
5. The method of claim 1, wherein the transmission type comprises a
unicast transmission type, further comprising: determining that at
least one feedback message was received; and resetting, based at
least in part on the at least one feedback message, the contention
window size for performing the one or more subsequent
transmissions.
6. The method of claim 5, wherein the at least one feedback message
comprises at least one negative-acknowledgement feedback message,
at least one acknowledgement feedback message, or both.
7. The method of claim 1, wherein the transmission type comprises a
unicast transmission type, further comprising: determining that no
feedback messages were received; and increasing, based at least in
part on the no feedback messages, the contention window size for
performing the one or more subsequent transmissions.
8. The method of claim 1, wherein the transmission type comprises a
unicast transmission type, further comprising: determining that at
least one acknowledgement feedback message was received; and
resetting, based at least in part on the at least one
acknowledgement feedback message, the contention window size for
performing the one or more subsequent transmissions.
9. The method of claim 1, wherein the transmission type comprises a
unicast transmission type, further comprising: determining that no
feedback messages were received or that a negative-acknowledgement
feedback message was received; and increasing, based at least in
part on the no feedback messages or the negative-acknowledgement
feedback message, the contention window size for performing the one
or more subsequent transmissions.
10. The method of claim 1, wherein the transmission type comprises
a connection-based groupcast transmission type, further comprising:
determining that at least one acknowledgement feedback message, at
least one negative-acknowledgement feedback message, or both, were
received from the one or more receiving devices; and resetting,
based at least in part on the at least one acknowledgement feedback
message, the at least one negative-acknowledgement feedback
message, or both, the contention window size for performing the one
or more subsequent transmissions.
11. The method of claim 10, further comprising: applying a
weighting factor to one or more negative-acknowledgement feedback
messages received from the one or more receiving devices, wherein
resetting the contention window size for performing the one or more
subsequent transmissions based at least in part on the weighting
factor.
12. The method of claim 1, wherein the transmission type comprises
a connection-based groupcast transmission type, further comprising:
determining that at least one acknowledgement feedback message, at
least one negative-acknowledgement feedback message, or both, were
received from the one or more receiving devices; determining that a
ratio of acknowledgement feedback messages,
negative-acknowledgement messages, or both, to an expected feedback
message count satisfies a threshold; and resetting, based at least
in part on the ratio satisfying the threshold, the contention
window size for performing the one or more subsequent
transmissions.
13. The method of claim 12, further comprising: applying a
weighting factor to each received negative-acknowledgement feedback
message to obtain a discounted negative-acknowledgement feedback
messages, wherein determining that a ratio satisfies the threshold
is based at least in part on the acknowledgement feedback message
and the discounted negative-acknowledgement feedback messages.
14. The method of claim 1, wherein the transmission type comprises
a connection-based groupcast transmission type, further comprising:
determining that at least one acknowledgement feedback message, at
least one negative-acknowledgement feedback message, or both, were
received from the one or more receiving devices; determining that a
ratio of acknowledgement feedback messages,
negative-acknowledgement messages, or both, to an expected feedback
message count fails to satisfy a threshold; and increasing, based
at least in part on the ratio failing to satisfy the threshold, the
contention window size for performing the one or more subsequent
transmissions.
15. The method of claim 14, further comprising: applying a
weighting factor to each received negative-acknowledgement feedback
message to obtain a discounted negative-acknowledgement feedback
messages, wherein determining that the ratio satisfies the
threshold is based at least in part on the acknowledgement feedback
message and the discounted negative-acknowledgement feedback
messages.
16. The method of claim 1, wherein the transmission type comprises
a connection-based groupcast transmission type, further comprising:
determining that at least one acknowledgement feedback message was
received from the one or more receiving devices; and resetting,
based at least in part on the at least one acknowledgement feedback
message, the contention window size for performing the one or more
subsequent transmissions.
17. The method of claim 1, wherein the transmission type comprises
a connection-based groupcast transmission type, further comprising:
determining that no acknowledgement feedback messages were received
from the one or more receiving devices; and increasing, based at
least in part on no acknowledgement feedback messages, the
contention window size for performing the one or more subsequent
transmissions.
18. The method of claim 1, wherein the transmission type comprises
a mixed transmission type, further comprising: determining, for one
or more transmission types of the mixed transmission types, that at
least one acknowledgement feedback message was received from the
one or more receiving devices; applying, based at least in part on
the transmission type of the mixed transmission type, a weighting
factor to each acknowledgement feedback message to obtain a
weighted acknowledgement metric; and resetting, based at least in
part on the weighted acknowledgement metric satisfying a threshold,
the contention window size for performing the one or more
subsequent transmissions.
19. The method of claim 18, wherein each transmission type of the
mixed transmission type is associated with a same weighting factor
or with different weighting factors.
20. The method of claim 18, wherein the mixed transmission type
comprise a unicast transmission type, a connection-based groupcast
transmission type, a connectionless-based groupcast transmission
type, or a combination thereof.
21. The method of claim 1, wherein the transmission type comprises
a mixed transmission type, further comprising: determining that no
feedback messages were received from the one or more receiving
devices; and maintaining, based at least in part on the no feedback
messages, the contention window size for performing the one or more
subsequent transmissions.
22. The method of claim 21, wherein the mixed transmission type
comprise a unicast transmission type, a connection-based groupcast
transmission type, a connectionless-based groupcast transmission
type, or a combination thereof.
23. An apparatus for wireless communication at a transmitting
device, comprising: a processor; memory coupled with the processor;
and instructions stored in the memory and executable by the
processor to cause the apparatus to: perform a first transmission
to one or more receiving devices, the first transmission associated
with a transmission type; determine a feedback response for the
first transmission based on monitoring for feedback messages from
the one or more receiving devices in response to the first
transmission; select a contention window size for performing one or
more subsequent transmissions based at least in part on the
feedback response and the transmission type; and perform the one or
more subsequent transmissions in accordance with a clear channel
assessment procedure using the selected contention window size.
24. The apparatus of claim 23, wherein the instructions are
executable by the processor to cause the apparatus to: determine
that no feedback messages were received from the one or more
receiving devices for the first transmission; determine that a
second transmission was multiplexed with the first transmission
during a same slot, the second transmission associated with a
different transmission type; and select, based at least in part on
receiving at least one feedback message for the second
transmission, the contention window size for performing the one or
more subsequent transmissions.
25. The apparatus of claim 23, wherein the instructions are
executable by the processor to cause the apparatus to: determine
that no feedback messages were received from the one or more
receiving devices; determine that no second transmission types were
multiplexed with the first transmission during a same slot; and
maintaining, base at least in part on no feedback messages and no
second transmission types being multiplexed with the first
transmission during the same slot, the contention window size for
performing the one or more subsequent transmissions.
26. The apparatus of claim 23, wherein the instructions are
executable by the processor to cause the apparatus to: determine
that at least one negative-acknowledgement feedback message was
received from the one or more receiving devices; and reset, based
at least in part on the at least one negative-acknowledgement
feedback message, the contention window size for performing the one
or more subsequent transmissions.
27. The apparatus of claim 23, wherein the instructions are
executable by the processor to cause the apparatus to: determine
that at least one feedback message was received; and resetting,
base at least in part on the at least one feedback message, the
contention window size for performing the one or more subsequent
transmissions.
28. The apparatus of claim 27, wherein the at least one feedback
message comprises at least one negative-acknowledgement feedback
message, at least one acknowledgement feedback message, or
both.
29. The apparatus of claim 23, wherein the instructions are
executable by the processor to cause the apparatus to: determine
that no feedback messages were received; and increasing, base at
least in part on the no feedback messages, the contention window
size for performing the one or more subsequent transmissions.
30. The apparatus of claim 23, wherein the instructions are
executable by the processor to cause the apparatus to: determine
that at least one acknowledgement feedback message was received;
and resetting, base at least in part on the at least one
acknowledgement feedback message, the contention window size for
performing the one or more subsequent transmissions.
Description
FIELD OF TECHNOLOGY
[0001] The following relates to wireless communications, including
contention window adjustment for new radio unlicensed/sidelink.
BACKGROUND
[0002] Wireless communication systems are widely deployed to
provide various types of communication content such as voice,
video, packet data, messaging, broadcast, and so on. These systems
may be capable of supporting communication with multiple users by
sharing the available system resources (e.g., time, frequency, and
power). Examples of such multiple-access systems include fourth
generation (4G) systems such as Long Term Evolution (LTE) systems,
LTE-Advanced (LTE-A) systems, or LTE-A Pro systems, and fifth
generation (5G) systems which may be referred to as New Radio (NR)
systems. These systems may employ technologies such as code
division multiple access (CDMA), time division multiple access
(TDMA), frequency division multiple access (FDMA), orthogonal
frequency division multiple access (OFDMA), or discrete Fourier
transform spread orthogonal frequency division multiplexing
(DFT-S-OFDM). A wireless multiple-access communications system may
include one or more base stations or one or more network access
nodes, each simultaneously supporting communication for multiple
communication devices, which may be otherwise known as user
equipment (UE).
SUMMARY
[0003] The described techniques relate to improved methods,
systems, devices, and apparatuses that support contention window
adjustment for new radio unlicensed/sidelink. Generally, the
described techniques provide various mechanisms that support
wireless communications in a wireless network. Broadly, aspects of
the described techniques support various mechanisms for hybrid
automatic repeat/request (HARQ) feedback rules to be adopted that
are on a transmission-type basis. The rules are specific to
particular transmission type(s) and the transmitting device adjusts
the contention window size based on the presence/absence, and/or
content of acknowledgement/negative-acknowledgement (ACK/NACK, or
more simply A/N) feedback messages. Accordingly, the transmitting
device may perform wireless transmissions using a specific
transmission type and/or a mixture of different transmission types
and then update its contention window size based on the presence or
absence of A/N feedback messages and/or the content of received
feedback messages. For example, the transmitting device may reset,
maintain, or increase its contention window size based on the HARQ
feedback. Accordingly, the transmitting device may be better able
to adapt its clear channel assessment (CCA) procedures using
contention window sizes based on more accurate channel
properties.
[0004] A method for wireless communication at a transmitting device
is described. The method may include performing a first
transmission to one or more receiving devices, the first
transmission associated with a transmission type, determining a
feedback response for the first transmission based on monitoring
for feedback messages from the one or more receiving devices in
response to the first transmission, selecting a contention window
size for performing one or more subsequent transmissions based on
the feedback response and the transmission type, and performing the
one or more subsequent transmissions in accordance with a CCA
procedure using the selected contention window size.
[0005] An apparatus for wireless communication at a transmitting
device is described. The apparatus may include a processor, memory
in electronic communication with the processor, and instructions
stored in the memory. The instructions may be executable by the
processor to cause the apparatus to perform a first transmission to
one or more receiving devices, the first transmission associated
with a transmission type, determine a feedback response for the
first transmission based on monitoring for feedback messages from
the one or more receiving devices in response to the first
transmission, select a contention window size for performing one or
more subsequent transmissions based on the feedback response and
the transmission type, and perform the one or more subsequent
transmissions in accordance with a CCA procedure using the selected
contention window size.
[0006] Another apparatus for wireless communication at a
transmitting device is described. The apparatus may include means
for performing a first transmission to one or more receiving
devices, the first transmission associated with a transmission
type, means for determining a feedback response for the first
transmission based on monitoring for feedback messages from the one
or more receiving devices in response to the first transmission,
means for selecting a contention window size for performing one or
more subsequent transmissions based on the feedback response and
the transmission type, and means for performing the one or more
subsequent transmissions in accordance with a CCA procedure using
the selected contention window size.
[0007] A non-transitory computer-readable medium storing code for
wireless communication at a transmitting device is described. The
code may include instructions executable by a processor to perform
a first transmission to one or more receiving devices, the first
transmission associated with a transmission type, determine a
feedback response for the first transmission based on monitoring
for feedback messages from the one or more receiving devices in
response to the first transmission, select a contention window size
for performing one or more subsequent transmissions based on the
feedback response and the transmission type, and perform the one or
more subsequent transmissions in accordance with a CCA procedure
using the selected contention window size.
[0008] In some examples of the method, apparatuses, and
non-transitory computer-readable medium described herein, and the
method, apparatuses, and non-transitory computer-readable medium
may include further operations, features, means, or instructions
for determining that no feedback messages were received from the
one or more receiving devices for the first transmission,
determining that a second transmission was multiplexed with the
first transmission during a same slot, the second transmission
associated with a different transmission type, and selecting, based
on receiving at least one feedback message for the second
transmission, the contention window size for performing the one or
more subsequent transmissions.
[0009] In some examples of the method, apparatuses, and
non-transitory computer-readable medium described herein, and the
method, apparatuses, and non-transitory computer-readable medium
may include further operations, features, means, or instructions
for determining that no feedback messages were received from the
one or more receiving devices, determining that no second
transmission types were multiplexed with the first transmission
during a same slot, and maintaining, based on no feedback messages
and no second transmission types being multiplexed with the first
transmission during the same slot, the contention window size for
performing the one or more subsequent transmissions.
[0010] In some examples of the method, apparatuses, and
non-transitory computer-readable medium described herein, and the
method, apparatuses, and non-transitory computer-readable medium
may include further operations, features, means, or instructions
for determining that at least one NACK feedback message was
received from the one or more receiving devices and resetting,
based on the at least one NACK feedback message, the contention
window size for performing the one or more subsequent
transmissions.
[0011] In some examples of the method, apparatuses, and
non-transitory computer-readable medium described herein, and the
method, apparatuses, and non-transitory computer-readable medium
may include further operations, features, means, or instructions
for determining that at least one feedback message was received and
resetting, based on the at least one feedback message, the
contention window size for performing the one or more subsequent
transmissions.
[0012] In some examples of the method, apparatuses, and
non-transitory computer-readable medium described herein, the at
least one feedback message includes at least one NACK feedback
message, at least one ACK feedback message, or both.
[0013] In some examples of the method, apparatuses, and
non-transitory computer-readable medium described herein, and the
method, apparatuses, and non-transitory computer-readable medium
may include further operations, features, means, or instructions
for determining that no feedback messages were received and
increasing, based on the no feedback messages, the contention
window size for performing the one or more subsequent
transmissions.
[0014] In some examples of the method, apparatuses, and
non-transitory computer-readable medium described herein, and the
method, apparatuses, and non-transitory computer-readable medium
may include further operations, features, means, or instructions
for determining that at least one ACK feedback message was received
and resetting, based on the at least one ACK feedback message, the
contention window size for performing the one or more subsequent
transmissions.
[0015] In some examples of the method, apparatuses, and
non-transitory computer-readable medium described herein, and the
method, apparatuses, and non-transitory computer-readable medium
may include further operations, features, means, or instructions
for determining that no feedback messages were received or that a
NACK feedback message was received from the one or more receiving
devices and increasing, based on the no feedback messages or the
NACK feedback message, the contention window size for performing
the one or more subsequent transmissions.
[0016] In some examples of the method, apparatuses, and
non-transitory computer-readable medium described herein, and the
method, apparatuses, and non-transitory computer-readable medium
may include further operations, features, means, or instructions
for determining that at least one ACK feedback message, at least
one NACK feedback message, or both, were received from the one or
more receiving devices and resetting, based on the at least one ACK
feedback message, the at least one NACK feedback message, or both,
the contention window size for performing the one or more
subsequent transmissions.
[0017] Some examples of the method, apparatuses, and non-transitory
computer-readable medium described herein may further include
operations, features, means, or instructions for applying a
weighting factor to one or more NACK feedback messages received
from the one or more receiving devices, where resetting the
contention window size for performing the one or more subsequent
transmissions based on the weighting factor.
[0018] In some examples of the method, apparatuses, and
non-transitory computer-readable medium described herein, and the
method, apparatuses, and non-transitory computer-readable medium
may include further operations, features, means, or instructions
for determining that at least one ACK feedback message, at least
one NACK feedback message, or both, were received from the one or
more receiving devices, determining that a ratio of ACK feedback
messages, NACK messages, or both, to an expected feedback message
count satisfies a threshold, and resetting, based on the ratio
satisfying the threshold, the contention window size for performing
the one or more subsequent transmissions.
[0019] Some examples of the method, apparatuses, and non-transitory
computer-readable medium described herein may further include
operations, features, means, or instructions for applying a
weighting factor to each received NACK feedback message to obtain a
discounted NACK feedback messages, where determining that a ratio
satisfies the threshold may be based on the ACK feedback message
and the discounted NACK feedback messages.
[0020] In some examples of the method, apparatuses, and
non-transitory computer-readable medium described herein, and the
method, apparatuses, and non-transitory computer-readable medium
may include further operations, features, means, or instructions
for determining that at least one ACK feedback message, at least
one NACK feedback message, or both, were received from the one or
more receiving devices, determining that a ratio of ACK feedback
messages, NACK messages, or both, to an expected feedback message
count fails to satisfy a threshold, and increasing, based on the
ratio failing to satisfy the threshold, the contention window size
for performing the one or more subsequent transmissions.
[0021] Some examples of the method, apparatuses, and non-transitory
computer-readable medium described herein may further include
operations, features, means, or instructions for applying a
weighting factor to each received NACK feedback message to obtain a
discounted NACK feedback messages, where determining that the ratio
satisfies the threshold may be based on the ACK feedback message
and the discounted NACK feedback messages.
[0022] In some examples of the method, apparatuses, and
non-transitory computer-readable medium described herein, and the
method, apparatuses, and non-transitory computer-readable medium
may include further operations, features, means, or instructions
for determining that at least one ACK feedback message was received
from the one or more receiving devices and resetting, based on the
at least one ACK feedback message, the contention window size for
performing the one or more subsequent transmissions.
[0023] In some examples of the method, apparatuses, and
non-transitory computer-readable medium described herein, and the
method, apparatuses, and non-transitory computer-readable medium
may include further operations, features, means, or instructions
for determining that no ACK feedback messages were received from
the one or more receiving devices and increasing, based on no ACK
feedback messages, the contention window size for performing the
one or more subsequent transmissions.
[0024] In some examples of the method, apparatuses, and
non-transitory computer-readable medium described herein, and the
method, apparatuses, and non-transitory computer-readable medium
may include further operations, features, means, or instructions
for determining, for one or more transmission types of the mixed
transmission types, that at least one ACK feedback message was
received from the one or more receiving devices, applying, based on
the transmission type of the mixed transmission type, a weighting
factor to each ACK feedback message to obtain a weighted ACK
metric, and resetting, based on the weighted ACK metric satisfying
a threshold, the contention window size for performing the one or
more subsequent transmissions.
[0025] In some examples of the method, apparatuses, and
non-transitory computer-readable medium described herein, each
transmission type of the mixed transmission type may be associated
with a same weighting factor or with different weighting
factors.
[0026] In some examples of the method, apparatuses, and
non-transitory computer-readable medium described herein, the mixed
transmission type include a unicast transmission type, a
connection-based groupcast transmission type, a
connectionless-based groupcast transmission type, or a combination
thereof.
[0027] In some examples of the method, apparatuses, and
non-transitory computer-readable medium described herein, and the
method, apparatuses, and non-transitory computer-readable medium
may include further operations, features, means, or instructions
for determining that no feedback messages were received from the
one or more receiving devices and maintaining, based on the no
feedback messages, the contention window size for performing the
one or more subsequent transmissions.
[0028] In some examples of the method, apparatuses, and
non-transitory computer-readable medium described herein, the mixed
transmission type include a unicast transmission type, a
connection-based groupcast transmission type, a
connectionless-based groupcast transmission type, or a combination
thereof.
BRIEF DESCRIPTION OF THE DRAWINGS
[0029] FIG. 1 illustrates an example of a wireless communication
system that supports contention window adjustment for new radio
unlicensed/sidelink in accordance with aspects of the present
disclosure.
[0030] FIG. 2 illustrates an example of a wireless communication
system that supports contention window adjustment for new radio
unlicensed/sidelink in accordance with aspects of the present
disclosure.
[0031] FIG. 3 illustrates an example of a wireless communication
system that supports contention window adjustment for new radio
unlicensed/sidelink in accordance with aspects of the present
disclosure.
[0032] FIG. 4 illustrates an example of a process that supports
contention window adjustment for new radio unlicensed/sidelink in
accordance with aspects of the present disclosure.
[0033] FIGS. 5 and 6 show block diagrams of devices that support
contention window adjustment for new radio unlicensed/sidelink in
accordance with aspects of the present disclosure.
[0034] FIG. 7 shows a block diagram of a communications manager
that supports contention window adjustment for new radio
unlicensed/sidelink in accordance with aspects of the present
disclosure.
[0035] FIG. 8 shows a diagram of a system including a UE that
supports contention window adjustment for new radio
unlicensed/sidelink in accordance with aspects of the present
disclosure.
[0036] FIG. 9 shows a diagram of a system including a base station
that supports contention window adjustment for new radio
unlicensed/sidelink in accordance with aspects of the present
disclosure.
[0037] FIGS. 10 through 14 show flowcharts illustrating methods
that support contention window adjustment for new radio
unlicensed/sidelink in accordance with aspects of the present
disclosure.
DETAILED DESCRIPTION
[0038] Wireless communication systems may use hybrid automatic
repeat/request (HARQ) feedback to improve reliability of wireless
transmissions. For the Uu interface (e.g., the cellular interface
between a base station and user equipment (UE)), rules are
generally established that determine how a receiving device
constructs and transmits HARQ feedback messages in a manner that
the transmitting device can properly interpret and respond to. Some
wireless communication systems may use sidelink channels to support
inter-UE communications, e.g., vehicle based communications,
UE-to-UE communications, etc. The sidelink channel uses a PC5
interface having multiple modes of operation (e.g., different
transmission types, such as unicast, broadcast, connection-based
groupcast, and connectionless-based groupcast). In some situations,
these sidelink transmission types may be associated with unlicensed
channels that use a clear channel assessment (CCA) procedure having
a contention window (e.g., a backoff window to be applied when the
channel is determined busy). However and depending on the
transmission type, the transmitting device may not know if there
are any receiving devices listening and/or which receiving devices
might be available to respond with HARQ feedback signaling. In the
CCA context, this may be especially problematic in that the
transmitting device may not be able to judge the channel condition
based on the presence or absence of
acknowledgement/negative-acknowledgement (ACK/NACK, or more simply
A/N) feedback. This prevents the transmitting device from adjusting
the contention window size in a manner that more accurately
responds to the channel conditions.
[0039] Aspects of the disclosure are initially described in the
context of wireless communication systems. Generally, the described
techniques provide various mechanisms that support wireless
communications in a wireless network. Broadly, aspects of the
described techniques support various mechanisms for HARQ feedback
rules to be adopted that are on a transmission-type basis. The
rules are specific to particular transmission type(s) and the
transmitting device adjusts the contention window size based on the
presence/absence and/or content of A/N feedback messages.
Accordingly, the transmitting device may perform wireless
transmissions using a specific transmission type and/or a mixture
of different transmission types and then update its contention
window size based on the presence or absence of A/N feedback
messages and/or the content of such feedback messages. For example,
the transmitting device may reset, maintain, or increase its
contention window size based on the HARQ feedback (e.g., the
feedback response from receiving device(s)). Accordingly, the
transmitting device may be better able to adapt its CCA procedures
using contention window sizes based on more accurate channel
properties.
[0040] Aspects of the disclosure are further illustrated by and
described with reference to apparatus diagrams, system diagrams,
and flowcharts that relate to contention window adjustment for new
radio unlicensed/sidelink.
[0041] FIG. 1 illustrates an example of a wireless communication
system 100 that supports contention window adjustment for new radio
unlicensed/sidelink in accordance with aspects of the present
disclosure. The wireless communication system 100 may include one
or more base stations 105, one or more UEs 115, and a core network
130. In some examples, the wireless communication system 100 may be
a Long Term Evolution (LTE) network, an LTE-Advanced (LTE-A)
network, an LTE-A Pro network, or a New Radio (NR) network. In some
examples, the wireless communication system 100 may support
enhanced broadband communications, ultra-reliable (e.g., mission
critical) communications, low latency communications,
communications with low-cost and low-complexity devices, or any
combination thereof.
[0042] The base stations 105 may be dispersed throughout a
geographic area to form the wireless communication system 100 and
may be devices in different forms or having different capabilities.
The base stations 105 and the UEs 115 may wirelessly communicate
via one or more communication links 125. Each base station 105 may
provide a coverage area 110 over which the UEs 115 and the base
station 105 may establish one or more communication links 125. The
coverage area 110 may be an example of a geographic area over which
a base station 105 and a UE 115 may support the communication of
signals according to one or more radio access technologies.
[0043] The UEs 115 may be dispersed throughout a coverage area 110
of the wireless communication system 100, and each UE 115 may be
stationary, or mobile, or both at different times. The UEs 115 may
be devices in different forms or having different capabilities.
Some example UEs 115 are illustrated in FIG. 1. The UEs 115
described herein may be able to communicate with various types of
devices, such as other UEs 115, the base stations 105, or network
equipment (e.g., core network nodes, relay devices, integrated
access and backhaul (IAB) nodes, or other network equipment), as
shown in FIG. 1.
[0044] The base stations 105 may communicate with the core network
130, or with one another, or both. For example, the base stations
105 may interface with the core network 130 through one or more
backhaul links 120 (e.g., via an S1, N2, N3, or other interface).
The base stations 105 may communicate with one another over the
backhaul links 120 (e.g., via an X2, Xn, or other interface) either
directly (e.g., directly between base stations 105), or indirectly
(e.g., via core network 130), or both. In some examples, the
backhaul links 120 may be or include one or more wireless
links.
[0045] One or more of the base stations 105 described herein may
include or may be referred to by a person having ordinary skill in
the art as a base transceiver station, a radio base station, an
access point, a radio transceiver, a NodeB, an eNodeB (eNB), a
next-generation NodeB or a giga-NodeB (either of which may be
referred to as a gNB), a Home NodeB, a Home eNodeB, or other
suitable terminology.
[0046] A UE 115 may include or may be referred to as a mobile
device, a wireless device, a remote device, a handheld device, or a
subscriber device, or some other suitable terminology, where the
"device" may also be referred to as a unit, a station, a terminal,
or a client, among other examples. A UE 115 may also include or may
be referred to as a personal electronic device such as a cellular
phone, a personal digital assistant (PDA), a tablet computer, a
laptop computer, or a personal computer. In some examples, a UE 115
may include or be referred to as a wireless local loop (WLL)
station, an Internet of Things (IoT) device, an Internet of
Everything (IoE) device, or a machine type communications (MTC)
device, among other examples, which may be implemented in various
objects such as appliances, or vehicles, meters, among other
examples.
[0047] The UEs 115 described herein may be able to communicate with
various types of devices, such as other UEs 115 that may sometimes
act as relays as well as the base stations 105 and the network
equipment including macro eNBs or gNBs, small cell eNBs or gNBs, or
relay base stations, among other examples, as shown in FIG. 1.
[0048] The UEs 115 and the base stations 105 may wirelessly
communicate with one another via one or more communication links
125 over one or more carriers. The term "carrier" may refer to a
set of radio frequency spectrum resources having a defined physical
layer structure for supporting the communication links 125. For
example, a carrier used for a communication link 125 may include a
portion of a radio frequency spectrum band (e.g., a bandwidth part
(BWP)) that is operated according to one or more physical layer
channels for a given radio access technology (e.g., LTE, LTE-A,
LTE-A Pro, NR). Each physical layer channel may carry acquisition
signaling (e.g., synchronization signals, system information),
control signaling that coordinates operation for the carrier, user
data, or other signaling. The wireless communication system 100 may
support communication with a UE 115 using carrier aggregation or
multi-carrier operation. A UE 115 may be configured with multiple
downlink component carriers and one or more uplink component
carriers according to a carrier aggregation configuration. Carrier
aggregation may be used with both frequency division duplexing
(FDD) and time division duplexing (TDD) component carriers.
[0049] In some examples (e.g., in a carrier aggregation
configuration), a carrier may also have acquisition signaling or
control signaling that coordinates operations for other carriers. A
carrier may be associated with a frequency channel (e.g., an
evolved universal mobile telecommunication system terrestrial radio
access (E-UTRA) absolute radio frequency channel number (EARFCN))
and may be positioned according to a channel raster for discovery
by the UEs 115. A carrier may be operated in a standalone mode
where initial acquisition and connection may be conducted by the
UEs 115 via the carrier, or the carrier may be operated in a
non-standalone mode where a connection is anchored using a
different carrier (e.g., of the same or a different radio access
technology).
[0050] The communication links 125 shown in the wireless
communication system 100 may include uplink transmissions from a UE
115 to a base station 105, or downlink transmissions from a base
station 105 to a UE 115. Carriers may carry downlink or uplink
communications (e.g., in an FDD mode) or may be configured to carry
downlink and uplink communications (e.g., in a TDD mode).
[0051] A carrier may be associated with a particular bandwidth of
the radio frequency spectrum, and in some examples the carrier
bandwidth may be referred to as a "system bandwidth" of the carrier
or the wireless communication system 100. For example, the carrier
bandwidth may be one of a number of determined bandwidths for
carriers of a particular radio access technology (e.g., 1.4, 3, 5,
10, 15, 20, 40, or 80 megahertz (MHz)). Devices of the wireless
communication system 100 (e.g., the base stations 105, the UEs 115,
or both) may have hardware configurations that support
communications over a particular carrier bandwidth or may be
configurable to support communications over one of a set of carrier
bandwidths. In some examples, the wireless communication system 100
may include base stations 105 or UEs 115 that support simultaneous
communications via carriers associated with multiple carrier
bandwidths. In some examples, each served UE 115 may be configured
for operating over portions (e.g., a sub-band, a BWP) or all of a
carrier bandwidth.
[0052] Signal waveforms transmitted over a carrier may be made up
of multiple subcarriers (e.g., using multi-carrier modulation (MCM)
techniques such as orthogonal frequency division multiplexing
(OFDM) or discrete Fourier transform spread OFDM (DFT-S-OFDM)). In
a system employing MCM techniques, a resource element may consist
of one symbol period (e.g., a duration of one modulation symbol)
and one subcarrier, where the symbol period and subcarrier spacing
are inversely related. The number of bits carried by each resource
element may depend on the modulation scheme (e.g., the order of the
modulation scheme, the coding rate of the modulation scheme, or
both). Thus, the more resource elements that a UE 115 receives and
the higher the order of the modulation scheme, the higher the data
rate may be for the UE 115. A wireless communications resource may
refer to a combination of a radio frequency spectrum resource, a
time resource, and a spatial resource (e.g., spatial layers or
beams), and the use of multiple spatial layers may further increase
the data rate or data integrity for communications with a UE
115.
[0053] One or more numerologies for a carrier may be supported,
where a numerology may include a subcarrier spacing (.DELTA.f) and
a cyclic prefix. A carrier may be divided into one or more BWPs
having the same or different numerologies. In some examples, a UE
115 may be configured with multiple BWPs. In some examples, a
single BWP for a carrier may be active at a given time and
communications for the UE 115 may be restricted to one or more
active BWPs.
[0054] The time intervals for the base stations 105 or the UEs 115
may be expressed in multiples of a basic time unit which may, for
example, refer to a sampling period of
T.sub.s=1/(.DELTA.f.sub.maxN.sub.f) seconds, where .DELTA.f.sub.max
may represent the maximum supported subcarrier spacing, and N.sub.f
may represent the maximum supported discrete Fourier transform
(DFT) size. Time intervals of a communications resource may be
organized according to radio frames each having a specified
duration (e.g., 10 milliseconds (ms)). Each radio frame may be
identified by a system frame number (SFN) (e.g., ranging from 0 to
1023).
[0055] Each frame may include multiple consecutively numbered
subframes or slots, and each subframe or slot may have the same
duration. In some examples, a frame may be divided (e.g., in the
time domain) into subframes, and each subframe may be further
divided into a number of slots. Alternatively, each frame may
include a variable number of slots, and the number of slots may
depend on subcarrier spacing. Each slot may include a number of
symbol periods (e.g., depending on the length of the cyclic prefix
prepended to each symbol period). In some wireless communication
systems 100, a slot may further be divided into multiple mini-slots
containing one or more symbols. Excluding the cyclic prefix, each
symbol period may contain one or more (e.g., N.sub.f) sampling
periods. The duration of a symbol period may depend on the
subcarrier spacing or frequency band of operation.
[0056] A subframe, a slot, a mini-slot, or a symbol may be the
smallest scheduling unit (e.g., in the time domain) of the wireless
communication system 100 and may be referred to as a transmission
time interval (TTI). In some examples, the TTI duration (e.g., the
number of symbol periods in a TTI) may be variable. Additionally,
or alternatively, the smallest scheduling unit of the wireless
communication system 100 may be dynamically selected (e.g., in
bursts of shortened TTIs (sTTIs)).
[0057] Physical channels may be multiplexed on a carrier according
to various techniques. A physical control channel and a physical
data channel may be multiplexed on a downlink carrier, for example,
using one or more of time division multiplexing (TDM) techniques,
frequency division multiplexing (FDM) techniques, or hybrid TDM-FDM
techniques. A control region (e.g., a control resource set
(CORESET)) for a physical control channel may be defined by a
number of symbol periods and may extend across the system bandwidth
or a subset of the system bandwidth of the carrier. One or more
control regions (e.g., CORESETs) may be configured for a set of the
UEs 115. For example, one or more of the UEs 115 may monitor or
search control regions for control information according to one or
more search space sets, and each search space set may include one
or multiple control channel candidates in one or more aggregation
levels arranged in a cascaded manner. An aggregation level for a
control channel candidate may refer to a number of control channel
resources (e.g., control channel elements (CCEs)) associated with
encoded information for a control information format having a given
payload size. Search space sets may include common search space
sets configured for sending control information to multiple UEs 115
and UE-specific search space sets for sending control information
to a specific UE 115.
[0058] Each base station 105 may provide communication coverage via
one or more cells, for example a macro cell, a small cell, a hot
spot, or other types of cells, or any combination thereof. The term
"cell" may refer to a logical communication entity used for
communication with a base station 105 (e.g., over a carrier) and
may be associated with an identifier for distinguishing neighboring
cells (e.g., a physical cell identifier (PCID), a virtual cell
identifier (VCID), or others). In some examples, a cell may also
refer to a geographic coverage area 110 or a portion of a
geographic coverage area 110 (e.g., a sector) over which the
logical communication entity operates. Such cells may range from
smaller areas (e.g., a structure, a subset of structure) to larger
areas depending on various factors such as the capabilities of the
base station 105. For example, a cell may be or include a building,
a subset of a building, or exterior spaces between or overlapping
with geographic coverage areas 110, among other examples.
[0059] A macro cell generally covers a relatively large geographic
area (e.g., several kilometers in radius) and may allow
unrestricted access by the UEs 115 with service subscriptions with
the network provider supporting the macro cell. A small cell may be
associated with a lower-powered base station 105, as compared with
a macro cell, and a small cell may operate in the same or different
(e.g., licensed, unlicensed) frequency bands as macro cells. Small
cells may provide unrestricted access to the UEs 115 with service
subscriptions with the network provider or may provide restricted
access to the UEs 115 having an association with the small cell
(e.g., the UEs 115 in a closed subscriber group (CSG), the UEs 115
associated with users in a home or office). A base station 105 may
support one or multiple cells and may also support communications
over the one or more cells using one or multiple component
carriers.
[0060] In some examples, a carrier may support multiple cells, and
different cells may be configured according to different protocol
types (e.g., MTC, narrowband IoT (NB-IoT), enhanced mobile
broadband (eMBB)) that may provide access for different types of
devices.
[0061] In some examples, a base station 105 may be movable and
therefore provide communication coverage for a moving geographic
coverage area 110. In some examples, different geographic coverage
areas 110 associated with different technologies may overlap, but
the different geographic coverage areas 110 may be supported by the
same base station 105. In other examples, the overlapping
geographic coverage areas 110 associated with different
technologies may be supported by different base stations 105. The
wireless communication system 100 may include, for example, a
heterogeneous network in which different types of the base stations
105 provide coverage for various geographic coverage areas 110
using the same or different radio access technologies.
[0062] The wireless communication system 100 may support
synchronous or asynchronous operation. For synchronous operation,
the base stations 105 may have similar frame timings, and
transmissions from different base stations 105 may be approximately
aligned in time. For asynchronous operation, the base stations 105
may have different frame timings, and transmissions from different
base stations 105 may, in some examples, not be aligned in time.
The techniques described herein may be used for either synchronous
or asynchronous operations.
[0063] Some UEs 115, such as MTC or IoT devices, may be low cost or
low complexity devices and may provide for automated communication
between machines (e.g., via Machine-to-Machine (M2M)
communication). M2M communication or MTC may refer to data
communication technologies that allow devices to communicate with
one another or a base station 105 without human intervention. In
some examples, M2M communication or MTC may include communications
from devices that integrate sensors or meters to measure or capture
information and relay such information to a central server or
application program that makes use of the information or presents
the information to humans interacting with the application program.
Some UEs 115 may be designed to collect information or enable
automated behavior of machines or other devices. Examples of
applications for MTC devices include smart metering, inventory
monitoring, water level monitoring, equipment monitoring,
healthcare monitoring, wildlife monitoring, weather and geological
event monitoring, fleet management and tracking, remote security
sensing, physical access control, and transaction-based business
charging.
[0064] Some UEs 115 may be configured to employ operating modes
that reduce power consumption, such as half-duplex communications
(e.g., a mode that supports one-way communication via transmission
or reception, but not transmission and reception simultaneously).
In some examples, half-duplex communications may be performed at a
reduced peak rate. Other power conservation techniques for the UEs
115 include entering a power saving deep sleep mode when not
engaging in active communications, operating over a limited
bandwidth (e.g., according to narrowband communications), or a
combination of these techniques. For example, some UEs 115 may be
configured for operation using a narrowband protocol type that is
associated with a defined portion or range (e.g., set of
subcarriers or resource blocks (RBs)) within a carrier, within a
guard-band of a carrier, or outside of a carrier.
[0065] The wireless communication system 100 may be configured to
support ultra-reliable communications or low-latency
communications, or various combinations thereof. For example, the
wireless communication system 100 may be configured to support
ultra-reliable low-latency communications (URLLC) or mission
critical communications. The UEs 115 may be designed to support
ultra-reliable, low-latency, or critical functions (e.g., mission
critical functions). Ultra-reliable communications may include
private communication or group communication and may be supported
by one or more mission critical services such as mission critical
push-to-talk (MCPTT), mission critical video (MCVideo), or mission
critical data (MCData). Support for mission critical functions may
include prioritization of services, and mission critical services
may be used for public safety or general commercial applications.
The terms ultra-reliable, low-latency, mission critical, and
ultra-reliable low-latency may be used interchangeably herein.
[0066] In some examples, a UE 115 may also be able to communicate
directly with other UEs 115 over a device-to-device (D2D)
communication link 135 (e.g., using a peer-to-peer (P2P) or D2D
protocol). One or more UEs 115 utilizing D2D communications may be
within the geographic coverage area 110 of a base station 105.
Other UEs 115 in such a group may be outside the geographic
coverage area 110 of a base station 105 or be otherwise unable to
receive transmissions from a base station 105. In some examples,
groups of the UEs 115 communicating via D2D communications may
utilize a one-to-many (1:M) system in which each UE 115 transmits
to every other UE 115 in the group. In some examples, a base
station 105 facilitates the scheduling of resources for D2D
communications. In other cases, D2D communications are carried out
between the UEs 115 without the involvement of a base station
105.
[0067] In some systems, the D2D communication link 135 may be an
example of a communication channel, such as a sidelink
communication channel, between vehicles (e.g., UEs 115). In some
examples, vehicles may communicate using vehicle-to-everything
(V2X) communications, vehicle-to-vehicle (V2V) communications, or
some combination of these. A vehicle may signal information related
to traffic conditions, signal scheduling, weather, safety,
emergencies, or any other information relevant to a V2X system. In
some examples, vehicles in a V2X system may communicate with
roadside infrastructure, such as roadside units, or with the
network via one or more network nodes (e.g., base stations 105)
using vehicle-to-network (V2N) communications, or with both.
[0068] The core network 130 may provide user authentication, access
authorization, tracking, Internet Protocol (IP) connectivity, and
other access, routing, or mobility functions. The core network 130
may be an evolved packet core (EPC) or 5G core (5GC), which may
include at least one control plane entity that manages access and
mobility (e.g., a mobility management entity (MME), an access and
mobility management function (AMF)) and at least one user plane
entity that routes packets or interconnects to external networks
(e.g., a serving gateway (S-GW), a Packet Data Network (PDN)
gateway (P-GW), or a user plane function (UPF)). The control plane
entity may manage non-access stratum (NAS) functions such as
mobility, authentication, and bearer management for the UEs 115
served by the base stations 105 associated with the core network
130. User IP packets may be transferred through the user plane
entity, which may provide IP address allocation as well as other
functions. The user plane entity may be connected to IP services
150 for one or more network operators. The IP services 150 may
include access to the Internet, Intranet(s), an IP Multimedia
Subsystem (IMS), or a Packet-Switched Streaming Service.
[0069] Some of the network devices, such as a base station 105, may
include subcomponents such as an access network entity 140, which
may be an example of an access node controller (ANC). Each access
network entity 140 may communicate with the UEs 115 through one or
more other access network transmission entities 145, which may be
referred to as radio heads, smart radio heads, or
transmission/reception points (TRPs). Each access network
transmission entity 145 may include one or more antenna panels. In
some configurations, various functions of each access network
entity 140 or base station 105 may be distributed across various
network devices (e.g., radio heads and ANCs) or consolidated into a
single network device (e.g., a base station 105).
[0070] The wireless communication system 100 may operate using one
or more frequency bands, typically in the range of 300 megahertz
(MHz) to 300 gigahertz (GHz). Generally, the region from 300 MHz to
3 GHz is known as the ultra-high frequency (UHF) region or
decimeter band because the wavelengths range from approximately one
decimeter to one meter in length. The UHF waves may be blocked or
redirected by buildings and environmental features, but the waves
may penetrate structures sufficiently for a macro cell to provide
service to the UEs 115 located indoors. The transmission of UHF
waves may be associated with smaller antennas and shorter ranges
(e.g., less than 100 kilometers) compared to transmission using the
smaller frequencies and longer waves of the high frequency (HF) or
very high frequency (VHF) portion of the spectrum below 300
MHz.
[0071] The wireless communication system 100 may also operate in a
super high frequency (SHF) region using frequency bands from 3 GHz
to 30 GHz, also known as the centimeter band, or in an extremely
high frequency (EHF) region of the spectrum (e.g., from 30 GHz to
300 GHz), also known as the millimeter band. In some examples, the
wireless communication system 100 may support millimeter wave (mmW)
communications between the UEs 115 and the base stations 105, and
EHF antennas of the respective devices may be smaller and more
closely spaced than UHF antennas. In some examples, this may
facilitate use of antenna arrays within a device. The propagation
of EHF transmissions, however, may be subject to even greater
atmospheric attenuation and shorter range than SHF or UHF
transmissions. The techniques disclosed herein may be employed
across transmissions that use one or more different frequency
regions, and designated use of bands across these frequency regions
may differ by country or regulating body.
[0072] The wireless communication system 100 may utilize both
licensed and unlicensed radio frequency spectrum bands. For
example, the wireless communication system 100 may employ License
Assisted Access (LAA), LTE-Unlicensed (LTE-U) radio access
technology, or NR technology in an unlicensed band such as the 5
GHz industrial, scientific, and medical (ISM) band. When operating
in unlicensed radio frequency spectrum bands, devices such as the
base stations 105 and the UEs 115 may employ carrier sensing for
collision detection and avoidance. In some examples, operations in
unlicensed bands may be based on a carrier aggregation
configuration in conjunction with component carriers operating in a
licensed band (e.g., LAA). Operations in unlicensed spectrum may
include downlink transmissions, uplink transmissions, P2P
transmissions, or D2D transmissions, among other examples.
[0073] A base station 105 or a UE 115 may be equipped with multiple
antennas, which may be used to employ techniques such as transmit
diversity, receive diversity, multiple-input multiple-output (MIMO)
communications, or beamforming. The antennas of a base station 105
or a UE 115 may be located within one or more antenna arrays or
antenna panels, which may support MIMO operations or transmit or
receive beamforming. For example, one or more base station antennas
or antenna arrays may be co-located at an antenna assembly, such as
an antenna tower. In some examples, antennas or antenna arrays
associated with a base station 105 may be located in diverse
geographic locations. A base station 105 may have an antenna array
with a number of rows and columns of antenna ports that the base
station 105 may use to support beamforming of communications with a
UE 115. Likewise, a UE 115 may have one or more antenna arrays that
may support various MIMO or beamforming operations. Additionally,
or alternatively, an antenna panel may support radio frequency
beamforming for a signal transmitted via an antenna port.
[0074] The base stations 105 or the UEs 115 may use MIMO
communications to exploit multipath signal propagation and increase
the spectral efficiency by transmitting or receiving multiple
signals via different spatial layers. Such techniques may be
referred to as spatial multiplexing. The multiple signals may, for
example, be transmitted by the transmitting device via different
antennas or different combinations of antennas. Likewise, the
multiple signals may be received by the receiving device via
different antennas or different combinations of antennas. Each of
the multiple signals may be referred to as a separate spatial
stream and may carry bits associated with the same data stream
(e.g., the same codeword) or different data streams (e.g.,
different codewords). Different spatial layers may be associated
with different antenna ports used for channel measurement and
reporting. MIMO techniques include single-user MIMO (SU-MIMO),
where multiple spatial layers are transmitted to the same receiving
device, and multiple-user MIMO (MU-MIMO), where multiple spatial
layers are transmitted to multiple devices.
[0075] Beamforming, which may also be referred to as spatial
filtering, directional transmission, or directional reception, is a
signal processing technique that may be used at a transmitting
device or a receiving device (e.g., a base station 105, a UE 115)
to shape or steer an antenna beam (e.g., a transmit beam, a receive
beam) along a spatial path between the transmitting device and the
receiving device. Beamforming may be achieved by combining the
signals communicated via antenna elements of an antenna array such
that some signals propagating at particular orientations with
respect to an antenna array experience constructive interference
while others experience destructive interference. The adjustment of
signals communicated via the antenna elements may include a
transmitting device or a receiving device applying amplitude
offsets, phase offsets, or both to signals carried via the antenna
elements associated with the device. The adjustments associated
with each of the antenna elements may be defined by a beamforming
weight set associated with a particular orientation (e.g., with
respect to the antenna array of the transmitting device or
receiving device, or with respect to some other orientation).
[0076] A base station 105 or a UE 115 may use beam sweeping
techniques as part of beam forming operations. For example, a base
station 105 may use multiple antennas or antenna arrays (e.g.,
antenna panels) to conduct beamforming operations for directional
communications with a UE 115. Some signals (e.g., synchronization
signals, reference signals, beam selection signals, or other
control signals) may be transmitted by a base station 105 multiple
times in different directions. For example, the base station 105
may transmit a signal according to different beamforming weight
sets associated with different directions of transmission.
Transmissions in different beam directions may be used to identify
(e.g., by a transmitting device, such as a base station 105, or by
a receiving device, such as a UE 115) a beam direction for later
transmission or reception by the base station 105.
[0077] Some signals, such as data signals associated with a
particular receiving device, may be transmitted by a base station
105 in a single beam direction (e.g., a direction associated with
the receiving device, such as a UE 115). In some examples, the beam
direction associated with transmissions along a single beam
direction may be determined based on a signal that was transmitted
in one or more beam directions. For example, a UE 115 may receive
one or more of the signals transmitted by the base station 105 in
different directions and may report to the base station 105 an
indication of the signal that the UE 115 received with a highest
signal quality or an otherwise acceptable signal quality.
[0078] In some examples, transmissions by a device (e.g., by a base
station 105 or a UE 115) may be performed using multiple beam
directions, and the device may use a combination of digital
precoding or radio frequency beamforming to generate a combined
beam for transmission (e.g., from a base station 105 to a UE 115).
The UE 115 may report feedback that indicates precoding weights for
one or more beam directions, and the feedback may correspond to a
configured number of beams across a system bandwidth or one or more
sub-bands. The base station 105 may transmit a reference signal
(e.g., a cell-specific reference signal (CRS), a channel state
information reference signal (CSI-RS)), which may be precoded or
unprecoded. The UE 115 may provide feedback for beam selection,
which may be a precoding matrix indicator (PMI) or codebook-based
feedback (e.g., a multi-panel type codebook, a linear combination
type codebook, a port selection type codebook). Although these
techniques are described with reference to signals transmitted in
one or more directions by a base station 105, a UE 115 may employ
similar techniques for transmitting signals multiple times in
different directions (e.g., for identifying a beam direction for
subsequent transmission or reception by the UE 115) or for
transmitting a signal in a single direction (e.g., for transmitting
data to a receiving device).
[0079] A receiving device (e.g., a UE 115) may try multiple receive
configurations (e.g., directional listening) when receiving various
signals from the base station 105, such as synchronization signals,
reference signals, beam selection signals, or other control
signals. For example, a receiving device may try multiple receive
directions by receiving via different antenna subarrays, by
processing received signals according to different antenna
subarrays, by receiving according to different receive beamforming
weight sets (e.g., different directional listening weight sets)
applied to signals received at multiple antenna elements of an
antenna array, or by processing received signals according to
different receive beamforming weight sets applied to signals
received at multiple antenna elements of an antenna array, any of
which may be referred to as "listening" according to different
receive configurations or receive directions. In some examples, a
receiving device may use a single receive configuration to receive
along a single beam direction (e.g., when receiving a data signal).
The single receive configuration may be aligned in a beam direction
determined based on listening according to different receive
configuration directions (e.g., a beam direction determined to have
a highest signal strength, highest signal-to-noise ratio (SNR), or
otherwise acceptable signal quality based on listening according to
multiple beam directions).
[0080] The wireless communication system 100 may be a packet-based
network that operates according to a layered protocol stack. In the
user plane, communications at the bearer or Packet Data Convergence
Protocol (PDCP) layer may be IP-based. A Radio Link Control (RLC)
layer may perform packet segmentation and reassembly to communicate
over logical channels. A Medium Access Control (MAC) layer may
perform priority handling and multiplexing of logical channels into
transport channels. The MAC layer may also use error detection
techniques, error correction techniques, or both to support
retransmissions at the MAC layer to improve link efficiency. In the
control plane, the Radio Resource Control (RRC) protocol layer may
provide establishment, configuration, and maintenance of an RRC
connection between a UE 115 and a base station 105 or a core
network 130 supporting radio bearers for user plane data. At the
physical layer, transport channels may be mapped to physical
channels.
[0081] The UEs 115 and the base stations 105 may support
retransmissions of data to increase the likelihood that data is
received successfully. Hybrid automatic repeat request (HARQ)
feedback is one technique for increasing the likelihood that data
is received correctly over a communication link 125. HARQ may
include a combination of error detection (e.g., using a cyclic
redundancy check (CRC)), forward error correction (FEC), and
retransmission (e.g., automatic repeat request (ARQ)). HARQ may
improve throughput at the MAC layer in poor radio conditions (e.g.,
low signal-to-noise conditions). In some examples, a device may
support same-slot HARQ feedback, where the device may provide HARQ
feedback in a specific slot for data received in a previous symbol
in the slot. In other cases, the device may provide HARQ feedback
in a subsequent slot, or according to some other time interval.
[0082] A transmitting device (e.g., a UE 115 and/or a base station
105 performing transmissions to a receiving device) may perform a
first transmission to one or more receiving devices, the first
transmission associated with a transmission type. The transmitting
device may determine a feedback response for the first transmission
based on monitoring for feedback messages from the one or more
receiving devices in response to the first transmission. The
transmitting device may select a contention window size for
performing one or more subsequent transmissions based at least in
part on the feedback response and the transmission type. The
transmitting device may perform the one or more subsequent
transmissions in accordance with a clear channel assessment
procedure using the selected contention window size.
[0083] FIG. 2 illustrates an example of a wireless communication
system 200 that supports contention window adjustment for new radio
unlicensed/sidelink in accordance with aspects of the present
disclosure. Wireless communication system may implement aspects of
wireless communication system 100. Wireless communication system
200 may include transmitting device 205, receiving device 210,
receiving device 215, and receiving device 220, with three
receiving devices being shown by way of example only. Transmitting
device 205 may be an example of a base station and/or a UE, which
may be examples of the corresponding devices described herein.
Receiving device 210, receiving device 215, and//or receiving
device 220 may be examples of a base station and/or UE, which may
be examples of the corresponding devices described herein.
Accordingly, references to a transmitting device and/or receiving
device may refer to a base station and/or UE, depending on the
context of the discussion.
[0084] Wireless communication system 200 may use sidelink channels
to support inter-UE communications, e.g., vehicle based
communications, UE-to-UE communications, etc. The sidelink channel
uses a PC5 interface having multiple modes of operation (e.g.,
different transmission types, such as unicast, broadcast,
connection-based groupcast, and connectionless-based groupcast).
The unicast transmission type may include the transmitting device
transmitting to a single receiving device where the transmitting
device can specifically request A/N feedback from the receiving
device for the transmission. The broadcast transmission type may
include the transmitting device transmitting to a group of
receiving devices in the neighborhood (e.g., nearby) where the
transmitting device does not request A/N feedback from the
receiving devices. The connection based groupcast transmission type
may include the transmitting device transmitting to a known group
of receiving devices where the transmitting device can request A/N
feedback from each receiving device. In this transmission type, the
receiving devices may use different feedback channel resources
(e.g., different physical sidelink feedback channel (PSFCH)
resources) to send the A/N feedback.
[0085] The connectionless groupcast transmission type may include
the transmitting device transmitting to an unknown group of
receiving devices (e.g., zone-based) where the transmitting device
can request NACK only feedback from the receiving UEs. All
receiving devices that receive the transmission may use the same
PSFCH resource to send feedback. A receiving device may send NACK
if the data portion of the transmission (e.g., the physical
sidelink shared channel (PSSCH)) is unable to be successfully
received and decoded. All PSFCH feedback (e.g., NACK feedback
messages) from all receiving devices may form a system frame number
(SFN) transmission at the transmitting device and the transmitting
device may retransmit if a single receiving device sends a NACK
feedback message.
[0086] In some situations, these sidelink transmission types may be
associated with unlicensed channels (e.g., NR-U) that use a CCA
procedure having a contention window (e.g., a backoff window to be
applied when the channel is determined busy). Generally and for the
Uu interface, the contention window adjustment for a category-four
(CAT-4) listen-before-talk (LBT) (e.g., a full CCA procedure) may
be based on the reference slot (e.g., usually the first slot of the
channel occupancy time (COT)). If ACK feedback is detected for the
transmission (e.g., PDSCH/PUSCH) on the reference slot, the
contention window size is reset to a minimum value. If NACK
feedback is detected, the transmitting device may increase (e.g.,
double) the contention window size. These Uu interface-type HARQ
techniques are designed for, and therefore only support a unicast
transmission type. In the Uu interface, NR-U may be associated with
broadcast transmission types, but such transmissions are for system
information delivery and there is no A/N feedback enabled.
Accordingly, the contention window size is not adjusted based on
the broadcast transmission type.
[0087] When performing sidelink communications on an unlicensed
channel, it may be beneficial to add a corresponding contention
window size adjustment procedure as well. In particular, it may be
beneficial to provide guidance such that a sidelink transmitting
device can properly adjust the contention window size if groupcast
or broadcast transmission types are transmitted in the contention
window update reference slot. This is because, depending on the
transmission type, the transmitting device may not even know if
there are any receiving devices listening and/or which receiving
devices might be available for A/N feedback. Such techniques may
provide guidance so the transmitting device is able to judge the
channel condition based on the presence or absence of A/N feedback,
and adjust its contention window size accordingly. These techniques
may improve behavior of the transmitting and receiving devices,
improve HARQ feedback signaling, and minimize unnecessary
retransmissions using valuable over-the-air resources.
[0088] Accordingly, aspects of the described techniques consider
the different transmission types separately (e.g., unicast,
connectionless groupcast, connection-based groupcast, and
broadcast, although NR-U HARQ procedures may be adopted for
broadcast transmission types on the unlicensed sidelink channel).
For unicast transmission types, NR-U provides contention window
size adjust for unicast transmissions. However, unicast
transmissions on the sidelink channel are different than unicast
transmissions in NR-U. On the sidelink channel, unicast
transmissions include both PSCCH and PSSCH transmissions that are
individually encoded and with separate cyclic redundancy check
(CRC) protection, but are always transmitted together. Accordingly,
aspects of the described HARQ techniques for a unicast transmission
type on the sidelink channel are different than the HARQ techniques
for a unicast transmission type on the Uu interface channel.
Accordingly, aspects of the described techniques address HARQ
behavior for each of the different transmission types as well as
behavior for a mixture of different transmission types.
[0089] Broadly, this may include transmitting device 205 performing
a transmission (e.g., a first transmission) to one or more
receiving devices (with three receiving devices being shown by way
of example only). The transmission may have a corresponding
transmission type (e.g., unicast, broadcast, connectionless
groupcast, or connection-based groupcast). Accordingly,
transmitting device 205, depending on the transmission type, may or
may not know if there are any receiving devices available to
receive and respond to the transmission. Transmitting device 205
may therefore monitor for feedback message(s) from receiving
device(s) (e.g., receiving device 210, receiving device 215, and/or
receiving device 220). Transmitting device 205 may monitor the same
resource for the feedback message(s) (e.g., a single PSFCH
resource) or different resources for the feedback message(s) (e.g.,
separate PSFCH resources) depending on the transmission type. Based
on the monitoring, transmitting device 205 may determine a feedback
response (e.g., whether there was ACK feedback, NACK feedback,
and/or erasure or absence of A/N feedback from receiving device(s))
for the transmission. Transmitting device 205 may use the feedback
response for the transmission and the corresponding transmission
type to select a contention window size for subsequent
transmissions accordingly. That is, transmitting device 205 may
maintain, reduce (e.g., reset), or increase (e.g., double) the
contention window size for CCA procedures associated with
subsequent transmission(s) based on the feedback response and
transmission type. This may provide rules that a transmitting
device may use to ensure more accurate contention window size
selection for CCA procedures that are based on current channel
conditions. This may improve communications on the unlicensed or
otherwise shared channel.
[0090] Accordingly, aspects of the described techniques provide
techniques that transmitting device 205 may follow when performing
transmissions of different transmission types on an unlicensed
channel. These techniques are on a per-transmission type basis
and/or for a mixture of different transmission types. Accordingly,
the specific rules to how/when the contention window size may be
updated are based on the transmission type and/or mixture of
different transmission types.
[0091] Starting first with a connectionless groupcast transmission
type (e.g., a connectionless-based groupcast transmission type), a
non-exhaustive list of different use cases is first described. In
use case 1, there are no other UEs (e.g., receiving devices) close
enough to receive the transmission. Therefore, there may be no
attempts to send NACK feedback. In use case 2, there are other UEs
(e.g., receiving devices) close enough to receive the transmission,
but there is a collision and no receiving device can successfully
receive and decode PSSCH. Accordingly, none of the receiving
devices may send NACK feedback. In use case 3, there are other UEs
(e.g., receiving devices) close enough to receive the transmission
and all receiving devices are able to successfully receive and
decode PSSCH. Accordingly, none of the receiving devices send NACK
feedback. In use case 4, there are other UEs (e.g., receiving
devices) close enough to receive the transmission, but at least one
receiving device failed to successfully receive and decode PSSCH.
Accordingly, at least one receiving device may send NACK feedback.
In use case 5, there are other UEs (e.g., receiving devices) close
enough to receive the transmission, but at least one receiving
device failed to successfully receive and decode PSSCH. However, in
this use case transmitting device 205 fails to successfully receive
and decode the NNACK feedback.
[0092] For the connectionless groupcast transmission type, the
conditions in which transmitting device 205 performs a
connectionless groupcast transmission type are different on a
sidelink channel as compared to a Uu interface channel. The
described techniques generally provide a different interpretation
of the feedback response for contention window size updates for a
connectionless groupcast transmission type. For example, a
receiving device operating on the sidelink channel typically only
transmits A/N when it is able to successfully receive and decode
sidelink control information (SCI). That is, a NR-U Uu interface
receiving device may transmit NACK even when PDCCH is not detected
(e.g., NACK is a filler in the HARQ codebook in PUCCH/PUSCH).
However, in a connectionless groupcast transmission type,
transmitting device 205 may not know who the receiving device(s)
are (e.g., per the use cases discussed above as well as other use
cases). That is, transmitting device 205 may not know whether any
of receiving device 210, receiving device 215, and/or receiving
device 220 are present and available to receive the connectionless
groupcast transmission. Accordingly, transmitting device 205 may
not know whether or not A/N feedback is to be expected and/or how
to interpret erasure (e.g., an absence of A/N feedback). The
receiving devices only send NACK on the same resource if the PSSCH
decoding fails (e.g., based on the distance from transmitting
device 205). That is, all receiving devices may send NACK using the
same time/frequency/spatial/code resource, so that the NACK(s) will
be in a SFN transmission. Transmitting device 205 may retransmit
the packet only if receiving a NACK from at least one receiving
device.
[0093] Application of the NR-U Uu feedback rules directly to a
connectionless groupcast transmission on a NR-U sidelink channel
may by problematic. The Uu interface typically interprets NACK as
an ACK indication (e.g., confirms that the receiving device was
able to at least receive and attempt to decode the transmission).
In this situation, transmitting device 205 would (e.g., following
the traditional NR-U Uu interface HARQ feedback rules) reset the
contention window size if no NACK is received and double the
contention window size if NACK feedback is received. This would
result in the contention window being reset for use cases 1, 2, 3,
and 5, and being doubled for use case 4. However, these scenarios
would be inaccurate and may disrupt communications between
transmitting device 205 and the receiving device(s). For use case
1, there are no receiving devices around to receive/respond to the
transmission, so it would be more beneficial if transmitting device
205 maintained the contention window size (e.g., rather than
resetting the contention window size). For use case 2, the
transmission failed due to collision, so it would be more
beneficial if transmitting device 205 doubled the contention window
size (e.g., not reset it). For use case 3, conventional rules to
reset the contention window size may be most beneficial (e.g.,
consistent with NR-U Uu behavior). For use case 4, the receiving
device(s) sending NACK feedback must have decoded PSCCH correctly.
This situation is different from NR-U Uu rules where sending NACK
feedback does not mean the PDCCH is successfully received and
decoded as the NACK feedback may be a filler in the HARQ codebook
when PDCCH is not detected (e.g., resulting in the transmitting
device not doubling the contention window size). For use case 5,
this is the same as use case 4 (e.g., consistent with NR-U Uu
behavior).
[0094] Accordingly and for the connectionless groupcast
transmission type, aspects of the described techniques may include
transmitting device 205 determining that no feedback messages were
received from the receiving device(s) (e.g., one or more of
receiving devices 210, 215, and/or 220). Transmitting device 205
may also determine that a second transmission during the reference
slot (e.g., the same slot) having a different transmission type was
multiplexed with the original transmission during the slot. Based
on the absence of A/N feedback messages for the transmission,
transmitting device 205 may use A/N feedback messages for the
second transmission (e.g., the transmission multiplexed
transmission) to select the contention window size. That is,
transmitting device 205 may use the A/N feedback response for the
other transmission type multiplexed in the reference slot to
determine the channel conditions and select a contention window
size accordingly.
[0095] Continuing with the connectionless groupcast transmission
type, transmitting device 205 may determine that there were no
other transmission types multiplexed with the transmission during
the reference slot (e.g., the same slot). In this situation,
transmitting device 205 may maintain the contention window size
based on the absence of A/N feedback for the transmission as well
as the absence of other transmission types multiplexed during the
slot. That is, transmitting device 205 may not interpret an absence
of A/N feedback as an indication of the current channel conditions,
e.g., the receiving devices in the neighborhood may have passed
PSSCH decoding and therefore do not provide a NACK indication.
[0096] If transmitting device 205 receives A/N feedback for the
connectionless group cast transmission, it may reset the contention
window size as the A/N feedback may indicate that the channel
conditions are performing within a threshold. This technique may be
applicable to use case 4, as well as other use cases.
[0097] Accordingly, transmitting device 205 may treat a NACK
feedback message (e.g., A/N feedback) as an acknowledgement for
PSCCH for connectionless groupcast transmissions (e.g., use the A/N
for PSCCH for SCI decoding as the indicator for contention window
updates). This may be based on the at least one NACK feedback from
at least one receiving device indicating that PSCCH can be decoded,
which implies little or not much interference at the PSCCH
resources. If transmitting device 205 determines that no feedback
messages were received from receiving device(s) associated with the
connectionless groupcast transmission (e.g., erasure), it may
maintain or reset the contention window size as is (e.g., as no
HARQ feedback may indicate that no receiving devices are close
enough, which may imply that the channel conditions are
acceptable). If transmitting device 205 receives a feedback message
indicating ACK for the connectionless groupcast transmission, it
may reset the contention window size.
[0098] In some aspects, such techniques for the connectionless
groupcast transmission type may be based on the particular use
case. For example and for use case 1, if transmitting device 205
determines that no feedback messages were received (e.g., erasure)
from any receiving device, it may be more beneficial to maintain
the contention window size (e.g., unchanged). As another example
and for use case 2, if transmitting device 205 determines that no
feedback messages were received (e.g., erasure), it may be more
beneficial to increase the contention window size (e.g., double the
contention window size). As another example for use cases 3 and/or
5, if transmitting device 205 determines that no feedback messages
are received (e.g., erasure), it may be more be more beneficial to
reset the contention window size.
[0099] Turning now to the unicast transmission types in the
contention window reference slot, transmitting device 205 may use
A/N feedback as indicators for the contention window size updates.
For both unicast and connection-based transmission types, the
receiving device may transmit A/N feedback via PSFCH when it
decodes SCI. That is, ACK feedback may be used to indicate
successfully receiving and decoding SCI and NACK feedback may be
used to indicate that the PSSCH following that SCI was not
successfully decoded. Accordingly, both ACK feedback and NACK
feedback may indicate that at least the SCI was successfully
transmitted in the reference signal, which may indicate that the
channel performance is at least somewhat acceptable. Generally,
PSCCH is designed to allow SCI-1 (e.g., SCI typically includes
SCI-1 transmitted via PSCCH and SCI-2 transmitted via PSSCH)
collisions, and is therefore robust to interference. Accordingly,
receiving a NACK feedback may imply that there is little
interference in PSCCH and PSSCH symbols.
[0100] Accordingly, when there is a unicast transmission in a
contention window reference slot, transmitting device 205 may use
ACK/NACK feedback as an indicator for contention window size
updates. In some examples, this may include transmitting device 205
treating both ACK or NACK for unicast transmission types as
acknowledgment for the purposes of contention window size updates,
and erasure or an absence of A/N feedback as a negative
acknowledgment or non-acknowledgement. For example, transmitting
device 205 may determine that at least one feedback message was
received from the receiving device(s). Accordingly, transmitting
device 205 may reset the contention window size based on the
feedback message(s) received from the receiving device(s). If
transmitting device 205 determines that no feedback messages have
been received from the receiving devices in response to the unicast
transmission, transmitting device 205 may increase the contention
window size based on the absence of feedback messages.
[0101] Accordingly, transmitting device 205 may reset the
contention window if A/N feedback is received as SCI has been
successfully decoded in the contention window update reference
slot. Transmitting device 205 may increase the contention window
size if no A/N feedback is received in the known, associated, or
otherwise corresponding PSFCH resources. This is because, for a
unicast transmission type, transmitting device 205 may know all of
the receive UEs and hence PSFCH resources to be used for feedback
messages. If no A/N feedback is transmitted by the receiving
devices, this may indicate the SCI decoding has failed, which may
be associated with interference during the contention window
reference slot. In some examples, successful decoding of SCI by the
receiving devices may include both SCI-1 and SCI-2. The receiving
devices may send A/N feedback only when there is limited
interference in the PSCCH region (e.g., for SCI-1) and/or the front
part of the PSSCH region that contains SCI-2, and hence SCI-1 and
SCI-2 may be decoded.
[0102] In some examples, transmitting device 205 may treat only ACK
feedback indications for a unicast transmission as acknowledgment,
and treat NACK or erasure as a negative acknowledgment. For
example, transmitting device 205 may determine that at least one
ACK feedback message was received from a receiving device and reset
the contention window size based on the acknowledgment message.
[0103] Transmitting device 205 may determine that no feedback
messages were received or that a NACK feedback message was received
from the receiving device. In this situation, transmitting device
205 may increase (e.g., double) the contention window size based on
the erasure or NACK indication. This may provide a conservative
approach using both PSCCH and PSSCH decoding results as the
reference for contention window size updates. Resetting the
contention window size if an ACK feedback message is received may
be based on the implication that both SCI and PSSCH have been
decoded successfully, and therefore there is limited interference
in both PSCCH and PSSCH.
[0104] Turning now to connection-based groupcast transmission
types, a connection-based groupcast transmission may be treated
similar to a unicast transmission type, except that the
transmitting device 205 may receive A/N feedback from all receiving
devices. Aspects of the described techniques use those multiple A/N
feedback responses from the receiving devices for contention window
size updates.
[0105] In one example, this may include transmitting device 205
treating A/N feedback messages as indicators for contention window
size updates. For example, in some situations transmitting device
205 may treat an ACK indication as an acknowledgment only or treat
A/N indications as acknowledgment for the transmission. For
example, transmitting device 205 may determine that at least one
ACK feedback message and/or at least one NACK feedback message was
received from the receiving device. In this example, transmitting
device 205 may reset the contention window size based on the A/N
feedback. In another example, transmitting device 205 may determine
that at least one ACK feedback message was received and reset the
contention window size based on the ACK feedback message.
[0106] In some aspects, a weighting factor may be applied to NACK
feedback messages received from receiving devices for the
connection-based groupcast transmission. That is, NACK feedback
indications may be discounted by a given weighting factor.
Transmitting device 205 may treat both ACK and NACK feedback
indications as acknowledgment, but may discount NACK indications by
the weighting factor. Although a NACK indication may imply
successful decoding of PSCCH, it also implies that PSSCH was unable
to be successfully decoded. Accordingly, the weighting factor may
treat a NACK indication as a percentage of an acknowledgement
indication (e.g., NACK=weighting factor multiplied by an ACK
indication, such as NACK is treated as 0.1 ACK indications for the
purposes of contention window size updates). Accordingly,
transmitting device 205 may apply the weighting factor to NACK
feedback messages received from the receiving devices and reset the
contention window size based on the weighting factor. For example,
if the percentage or total number of ACK indications (which
includes all ACK indications and the weighted/discounted NACK
indications) reaches a threshold, transmitting device 205 may reset
the contention window size. If the total number of ACK indications
fail to reach the threshold, transmitting device 205 may maintain
or increase the contention window size.
[0107] In some situations, transmitting device 205 may, for a
connection-based groupcast transmission type, update the contention
window size based on receiving multiple A/N feedback messages. In
one example, this may include transmitting device 205 resetting the
contention window size if the percentage of ACK feedback messages
is greater than a threshold, otherwise transmitting device 205 may
increase (e.g., double) the contention window size. That is,
transmitting device 205 may determine that at least one ACK and/or
NACK feedback message were received from the receiving device.
Transmitting device 205 may determine the ratio of ACK and/or NACK
feedback messages with respect to an expected feedback message
count (e.g., based on the number of feedback messages that
transmitting device 205 is expecting to receive on PSFCH
resource(s)). Transmitting device 205 may increase the contention
window size if the ratio fails to satisfy a threshold and maintain
or reset the contention window size if the ratio satisfies a
threshold.
[0108] Accordingly, in this example transmitting device 205 may
know the number of receiving devices expected to receive the
connection-based groupcast transmission, and therefore may know the
total number of expected feedback messages to be received. If the
preconfigured percentage (e.g., the ratio) of receiving devices are
able to successfully receive and decode PSCCH/PSSCH, this may
provide an indication that the channel is clear and therefore the
contention window size can be reset or maintained as is.
[0109] In some aspects, this may include a transmitting device 205
applying the weighting factor for each NACK feedback message
indication to obtain a discounted NACK feedback message. Again, the
ratio of ACK feedback messages and discounted NACK feedback
messages to the expected feedback message count may be used for
contention window size updates.
[0110] In some situations and continuing with the connection-based
groupcast transmission type discussion, transmitting device 205 may
reset the contention window size if at least one of the feedback
messages received from receiving devices in response to the
connection-based groupcast transmission is an ACK feedback
indication. Otherwise, transmitting device 205 may increase (e.g.,
double) the contention window size. That is, transmitting device
205 may determine that at least one ACK feedback message has been
received from the receiving devices and, in response, reset the
contention window size. If transmitting device 205 determines that
no ACK feedback messages were received from the receiving devices,
transmitting device 205 may increase the contention window
size.
[0111] Accordingly, transmitting device 205 may focus on whether
there is interference near itself (e.g., due to a hidden node
problem). If there is no interference nearby, transmitting device
205 may determine that there is at least one receiving device that
can successfully decode SCI/PSSCH and transmit the ACK
indication.
[0112] As discussed above and in the broadcast transmission type
scenario, transmitting device 205 may refrain from performing
contention window size updates based on broadcast transmissions.
That is, broadcast transmissions may not support A/N feedback
message signaling, and therefore contention window size adjustments
based on the transmitting device 205 performing a transmission
having a broadcast transmission type may be avoided.
[0113] In some situations, there may be a mixture of transmission
types being transmitted during the contention window update
reference slot. For example, transmitting device 205 may perform a
mixed transmission during the reference slot that includes a
mixture of a unicast transmission, connection-based groupcast
transmission, connection less groupcast transmissions, and the
like. In this situation, transmitting device 205 may consider the
mixture of transmission types during the contention window
reference slot when making contention window size updates.
[0114] In one example of the mixed transmission type scenario, this
may include the mixed transmission types being multiplexed in the
same reference slot. Transmitting device 205 may combine ACK
feedback message indications for contention window size updates. In
some aspects, this may include application of the weighting factor
to each ACK feedback message. For example, transmitting device 205
may determine that at least one ACK feedback message was received
from receiving devices for one or more transmission types of the
mixture of transmission types. Transmitting device 205 may apply
the weighting factor to each ACK feedback message to identify or
otherwise obtain a weighted ACK metric. Transmitting device 205 may
reset the contention window size when the weighted ACK metric
satisfies a threshold or maintain/increase the contention window
size when the weighted ACK metric fails to satisfy a threshold. In
some examples, the different transmission types of the mixed
transmission type may be associated with the same weighting factor
or with different weighting factors.
[0115] For example, transmitting device 205 may define the
percentage of ACK feedback messages for a mix of transmission types
(e.g., may define the threshold) as
P.sub.acknowledge=(.varies..sub.unicast.times.P.sub.unicast+.varies..sub.-
CB.times.P.sub.CB+.varies..sub.CL.times.P.sub.CL)/(.varies..sub.unicast+.v-
aries..sub.CB+.varies..sub.CL). P.sub.unicast may refer to the
percentage of ACK feedback messages received over multiple unicast
transmissions. P.sub.CB may refer to the percentage of ACK feedback
messages received over multiple PSFCH resources pairs for the group
of receiving devices and possible multiple groupcast packets. In
some situations, P.sub.CB may be set to "1" if receiving an ACK
feedback message from at least one receiving device. P.sub.CL may
refer to the percentage of ACK feedback messages received over
multiple connectionless groupcast transmissions.
.varies..sub.unicast, .varies..sub.CB, and .varies..sub.CL may
refer to positive weighting factors configured for each
transmission type in the mixed transmission type scenario, which
may be the same or may be different for each transmission type. For
example, for a mixture of unicast, connection-based groupcast, and
connectionless groupcast transmission types, .varies..sub.CL may be
set to "0" as connectionless groupcast feedback may not provide as
much information regarding contention window size updates as
compared to unicast and connection-based groupcast transmission
types. If P.sub.acknowledge is greater than a threshold, then
transmitting device 205 may reset the contention window size. If
not, transmitting device 205 may increase (e.g., double) the
contention window size.
[0116] In some mixed transmission type situations, there may be no
receiving devices nearby to receive the transmissions from
transmitting device 205. In that situation, treating erasure (e.g.,
an absence of feedback messages) as non-acknowledgement, and
therefore increasing the contention window size, may be
undesirable. Instead, maintaining the contention window size may be
more appropriate in this situation. Accordingly, in some situations
transmitting device 205 may determine that no feedback messages
were received and, therefore, maintain the contention window size.
In some aspects, this may include a determination that no feedback
messages were received during a time period, e.g., for a threshold
number of slots. Accordingly, transmitting device 205 may determine
that no feedback messages were received during the time period and
maintain the contention window size. This may address the situation
where a lack of feedback messages indicates that there are no
receiving devices nearby, or that such receiving devices are
blocked by an interfering transmission, rather than indicting that
the channel performance is poor.
[0117] FIG. 3 illustrates an example of a wireless communication
system 300 that supports contention window adjustment for new radio
unlicensed/sidelink in accordance with aspects of the present
disclosure. Wireless communication system 300 may implement aspects
of wireless communication systems 100 and/or 200. Wireless
communication system 300 may include transmitting device 305,
receiving device 310, receiving device 315, receiving device 320,
and hidden node 325, which may be examples of the corresponding
devices described herein.
[0118] As discussed above, the described techniques provide various
techniques that may be adopted for contention window size updates
based on the specific transmission type(s) being performed by
transmitting device 305. For example, transmitting device 305 may
perform a transmission (e.g., a first transmission) to one or more
receiving devices, with three receiving devices shown by way of
example only. This may include transmitting device 305 performing a
wireless transmission to receiving device 310, receiving device
315, and/or receiving device 320. The transmission may be or have
an associated transmission type (e.g., unicast transmission type,
connection-based groupcast transmission type, and/or connectionless
groupcast transmission type). Transmitting device 305 may monitor
for feedback messages from the receiving device(s) to determine the
feedback response for the transmission. That is, transmitting
device 305 may determine whether ACK feedback messages, NACK
feedback messages, or erasure (e.g., no feedback messages) for the
transmission.
[0119] Based on the feedback response, transmitting device 305 may
select a contention window size for subsequent transmissions. For
example, transmitting device 305 may maintain the contention window
size as is, may increase the contention window size (e.g., double),
or may reset the contention window size (e.g., to a default size)
based on the feedback response and the transmission type.
[0120] One solution discussed above may include transmitting device
305, for connection-based groupcast transmissions, updating the
contention window based on multiple A/N feedback messages. For
example, transmitting device 305 may reset the contention window
size if the percentage (e.g., ratio) of acknowledgement messages
(ACK or NACK feedback messages) with respect to an expected number
of feedback messages satisfies a threshold. As the number of
receiving devices in a connection-based groupcast transmission
scenario may be known by transmitting device 305, updating the
contention window size based on the ratio satisfying the threshold
may be based on the assumption that the channel is clean.
[0121] However, wireless communication system 300 illustrates an
example where transmitting device 305 may be better suited to reset
the contention window size based on receiving at least one feedback
message from a receiving device. For example, wireless
communication system 300 illustrates an example where receiving
device 315 and receiving device 320 may be known receiving devices
for the connection-based groupcast transmission, and therefore
expected to transmit feedback messages in response to the
transmission. However, hidden node 325 may be an unknown node to
transmitting device 305 and may be performing its own transmission
that interferes with reception of the connection-based groupcast
transmission by receiving device 315 and receiving device 320. As
receiving device 315 and receiving device 320 are unable to receive
the transmission from transmitting device 305, they may not
transmit feedback messages (e.g., erasure).
[0122] In this situation, it may be more appropriate for
transmitting device 305 to reset the contention window size of at
least one ACK feedback message is received from any of the
receiving devices, such as from receiving device 310. Accordingly,
transmitting device 305 may reset the contention window size if at
least one ACK feedback message is received or increase the
contention window size if no ACK feedback messages are
received.
[0123] FIG. 4 illustrates an example of a process 400 that supports
contention window adjustment for new radio unlicensed/sidelink in
accordance with aspects of the present disclosure. Process 400 may
implement aspects of wireless communication systems 100, 200,
and/or 300. Aspects of process 400 may be implemented by or
implemented at transmitting device 405, receiving device 410,
and/or receiving device 4115, which may be examples of the
corresponding devices described herein.
[0124] At 420, transmitting device 405 may transmit or otherwise
provide a transmission (e.g., a first transmission) to one or more
receiving devices, such as receiving device 410 and receiving
device 415. The transmission may be of or associated with a
transmission type, such as a unicast transmission type, a
connection-based groupcast transmission type, a connectionless
transmission type, and the like. The transmission may be performed
using sidelink channel(s) in some examples.
[0125] At 425, transmitting device 405 may determine a feedback
response for the transmission based on monitoring for feedback
messages from receiving device 410 and/or receiving device 415. In
some examples (e.g., depending on the transmission type),
transmitting device 405 may know which receiving devices are
expected to transmit a feedback message. In other examples,
transmitting device 405 may not know which receiving devices are
expected to transmit a feedback message. For example, some
transmission types are associated with know and shared PSFCH
resources, which transmitting device 405 may monitor for feedback
messages. Generally, the feedback response may be based on the
presence or absence of feedback messages and/or based on the
content of the feedback messages (e.g., ACK or NACK feedback
messages). In some situations, transmitting device 405 may apply a
weighting factor to NACK feedback messages (e.g., to derive a
discounted NACK feedback message). For example, transmitting device
405 may use the discounted NACK feedback message(s) (alone or in
combination with ACK feedback messages) to determine the feedback
response, and the resulting contention window size updates.
[0126] At 430, transmitting device 405 may select a contention
window size for subsequent transmissions based on the feedback
response and transmission type. For example, transmitting device
may increase (e.g., double) the contention window size, may reset
the contention window size (e.g., to a default value), or may
maintain the contention window size as is based on the feedback
response and transmission type. Accordingly, transmitting device
405 may use the feedback response for specific transmission types
to estimate channel performance, and update the contention window
size for future CCA procedures to more accurately mitigate channel
conditions.
[0127] At 435, transmitting device 405 may perform such subsequent
transmissions to receiving device 410 and/or receiving device 415
based on the selected or updated contention window size. This may
improve sidelink communications via unlicensed channels accounting
for different transmission types used for such sidelink
communications.
[0128] FIG. 5 shows a block diagram 500 of a device 505 that
supports contention window adjustment for new radio
unlicensed/sidelink in accordance with aspects of the present
disclosure. The device 505 may be an example of aspects of a UE 115
or a base station 105 as described herein. The device 505 may
include a receiver 510, a transmitter 515, and a communications
manager 520. The device 505 may also include a processor. Each of
these components may be in communication with one another (e.g.,
via one or more buses).
[0129] The receiver 510 may provide a means for receiving
information such as packets, user data, control information, or any
combination thereof associated with various information channels
(e.g., control channels, data channels, information channels
related to contention window adjustment for new radio
unlicensed/sidelink). Information may be passed on to other
components of the device 505. The receiver 510 may utilize a single
antenna or a set of multiple antennas.
[0130] The transmitter 515 may provide a means for transmitting
signals generated by other components of the device 505. For
example, the transmitter 515 may transmit information such as
packets, user data, control information, or any combination thereof
associated with various information channels (e.g., control
channels, data channels, information channels related to contention
window adjustment for new radio unlicensed/sidelink). In some
examples, the transmitter 515 may be co-located with a receiver 510
in a transceiver module. The transmitter 515 may utilize a single
antenna or a set of multiple antennas.
[0131] The communications manager 520, the receiver 510, the
transmitter 515, or various combinations thereof or various
components thereof may be examples of means for performing various
aspects of contention window adjustment for new radio
unlicensed/sidelink as described herein. For example, the
communications manager 520, the receiver 510, the transmitter 515,
or various combinations or components thereof may support a method
for performing one or more of the functions described herein.
[0132] In some examples, the communications manager 520, the
receiver 510, the transmitter 515, or various combinations or
components thereof may be implemented in hardware (e.g., in
communications management circuitry). The hardware may include a
processor, a digital signal processor (DSP), an
application-specific integrated circuit (ASIC), a
field-programmable gate array (FPGA) or other programmable logic
device, a discrete gate or transistor logic, discrete hardware
components, or any combination thereof configured as or otherwise
supporting a means for performing the functions described in the
present disclosure. In some examples, a processor and memory
coupled with the processor may be configured to perform one or more
of the functions described herein (e.g., by executing, by the
processor, instructions stored in the memory).
[0133] Additionally, or alternatively, in some examples, the
communications manager 520, the receiver 510, the transmitter 515,
or various combinations or components thereof may be implemented in
code (e.g., as communications management software or firmware)
executed by a processor. If implemented in code executed by a
processor, the functions of the communications manager 520, the
receiver 510, the transmitter 515, or various combinations or
components thereof may be performed by a general-purpose processor,
a DSP, a central processing unit (CPU), an ASIC, an FPGA, or any
combination of these or other programmable logic devices (e.g.,
configured as or otherwise supporting a means for performing the
functions described in the present disclosure).
[0134] In some examples, the communications manager 520 may be
configured to perform various operations (e.g., receiving,
monitoring, transmitting) using or otherwise in cooperation with
the receiver 510, the transmitter 515, or both. For example, the
communications manager 520 may receive information from the
receiver 510, send information to the transmitter 515, or be
integrated in combination with the receiver 510, the transmitter
515, or both to receive information, transmit information, or
perform various other operations as described herein.
[0135] The communications manager 520 may support wireless
communication at a transmitting device in accordance with examples
as disclosed herein. For example, the communications manager 520
may be configured as or otherwise support a means for performing a
first transmission to one or more receiving devices, the first
transmission associated with a transmission type. The
communications manager 520 may be configured as or otherwise
support a means for determining a feedback response for the first
transmission based on monitoring for feedback messages from the one
or more receiving devices in response to the first transmission.
The communications manager 520 may be configured as or otherwise
support a means for selecting a contention window size for
performing one or more subsequent transmissions based on the
feedback response and the transmission type. The communications
manager 520 may be configured as or otherwise support a means for
performing the one or more subsequent transmissions in accordance
with a clear channel assessment procedure using the selected
contention window size.
[0136] By including or configuring the communications manager 520
in accordance with examples as described herein, the device 505
(e.g., a processor controlling or otherwise coupled to the receiver
510, the transmitter 515, the communications manager 520, or a
combination thereof) may support techniques for improving
contention window size updates for CCA procedures performed on a
sidelink channel based on the feedback response for a transmission
and the corresponding transmission type of that transmission.
[0137] FIG. 6 shows a block diagram 600 of a device 605 that
supports contention window adjustment for new radio
unlicensed/sidelink in accordance with aspects of the present
disclosure. The device 605 may be an example of aspects of a device
505, a UE 115, or a base station 105 as described herein. The
device 605 may include a receiver 610, a transmitter 615, and a
communications manager 620. The device 605 may also include a
processor. Each of these components may be in communication with
one another (e.g., via one or more buses).
[0138] The receiver 610 may provide a means for receiving
information such as packets, user data, control information, or any
combination thereof associated with various information channels
(e.g., control channels, data channels, information channels
related to contention window adjustment for new radio
unlicensed/sidelink). Information may be passed on to other
components of the device 605. The receiver 610 may utilize a single
antenna or a set of multiple antennas.
[0139] The transmitter 615 may provide a means for transmitting
signals generated by other components of the device 605. For
example, the transmitter 615 may transmit information such as
packets, user data, control information, or any combination thereof
associated with various information channels (e.g., control
channels, data channels, information channels related to contention
window adjustment for new radio unlicensed/sidelink). In some
examples, the transmitter 615 may be co-located with a receiver 610
in a transceiver module. The transmitter 615 may utilize a single
antenna or a set of multiple antennas.
[0140] The device 605, or various components thereof, may be an
example of means for performing various aspects of contention
window adjustment for new radio unlicensed/sidelink as described
herein. For example, the communications manager 620 may include a
transmission manager 625, a feedback response manager 630, a
contention window size 635, or any combination thereof. The
communications manager 620 may be an example of aspects of a
communications manager 520 as described herein. In some examples,
the communications manager 620, or various components thereof, may
be configured to perform various operations (e.g., receiving,
monitoring, transmitting) using or otherwise in cooperation with
the receiver 610, the transmitter 615, or both. For example, the
communications manager 620 may receive information from the
receiver 610, send information to the transmitter 615, or be
integrated in combination with the receiver 610, the transmitter
615, or both to receive information, transmit information, or
perform various other operations as described herein.
[0141] The communications manager 620 may support wireless
communication at a transmitting device in accordance with examples
as disclosed herein. The transmission manager 625 may be configured
as or otherwise support a means for performing a first transmission
to one or more receiving devices, the first transmission associated
with a transmission type. The feedback response manager 630 may be
configured as or otherwise support a means for determining a
feedback response for the first transmission based on monitoring
for feedback messages from the one or more receiving devices in
response to the first transmission. The contention window size 635
may be configured as or otherwise support a means for selecting a
contention window size for performing one or more subsequent
transmissions based on the feedback response and the transmission
type. The transmission manager 625 may be configured as or
otherwise support a means for performing the one or more subsequent
transmissions in accordance with a clear channel assessment
procedure using the selected contention window size.
[0142] FIG. 7 shows a block diagram 700 of a communications manager
720 that supports contention window adjustment for new radio
unlicensed/sidelink in accordance with aspects of the present
disclosure. The communications manager 720 may be an example of
aspects of a communications manager 520, a communications manager
620, or both, as described herein. The communications manager 720,
or various components thereof, may be an example of means for
performing various aspects of contention window adjustment for new
radio unlicensed/sidelink as described herein. For example, the
communications manager 720 may include a transmission manager 725,
a feedback response manager 730, a contention window size 735, a
connectionless groupcast transmission manager 740, a unicast
transmission manager 745, a connection-based groupcast transmission
manager 750, a mixed transmission type 760, or any combination
thereof. Each of these components may communicate, directly or
indirectly, with one another (e.g., via one or more buses).
[0143] The communications manager 720 may support wireless
communication at a transmitting device in accordance with examples
as disclosed herein. The transmission manager 725 may be configured
as or otherwise support a means for performing a first transmission
to one or more receiving devices, the first transmission associated
with a transmission type. The feedback response manager 730 may be
configured as or otherwise support a means for determining a
feedback response for the first transmission based on monitoring
for feedback messages from the one or more receiving devices in
response to the first transmission. The contention window size 735
may be configured as or otherwise support a means for selecting a
contention window size for performing one or more subsequent
transmissions based on the feedback response and the transmission
type. In some examples, the transmission manager 725 may be
configured as or otherwise support a means for performing the one
or more subsequent transmissions in accordance with a clear channel
assessment procedure using the selected contention window size.
[0144] In some examples, the connectionless groupcast transmission
manager 740 may be configured as or otherwise support a means for
determining that no feedback messages were received from the one or
more receiving devices for the first transmission. In some
examples, the connectionless groupcast transmission manager 740 may
be configured as or otherwise support a means for determining that
a second transmission type was multiplexed with the first
transmission during a same slot, the second transmission associated
with a different transmission type. In some examples, the
connectionless groupcast transmission manager 740 may be configured
as or otherwise support a means for selecting, based on receiving
at least one feedback message for the second transmission, the
contention window size for performing the one or more subsequent
transmissions. In some examples, the connectionless groupcast
transmission manager 740 may be configured as or otherwise support
a means for determining that at least one NACK feedback message was
received from the one or more receiving devices. In some examples,
the connectionless groupcast transmission manager 740 may be
configured as or otherwise support a means for resetting, based at
least in part on the at least one negative-acknowledgement feedback
message, the contention window size for e performing the one or
more subsequent transmissions.
[0145] In some examples, the connectionless groupcast transmission
manager 740 may be configured as or otherwise support a means for
determining that no feedback messages were received from the one or
more receiving devices. In some examples, the connectionless
groupcast transmission manager 740 may be configured as or
otherwise support a means for determining that no second
transmission types were multiplexed with the first transmission
during a same slot. In some examples, the connectionless groupcast
transmission manager 740 may be configured as or otherwise support
a means for maintaining, based on no feedback messages and no
second transmission types being multiplexed with the first
transmission during the same slot, the contention window size for
performing the one or more subsequent transmissions.
[0146] In some examples, the unicast transmission manager 745 may
be configured as or otherwise support a means for determining that
at least one feedback message was received. In some examples, the
unicast transmission manager 745 may be configured as or otherwise
support a means for resetting, based on the at least one feedback
message, the contention window size for performing the one or more
subsequent transmissions.
[0147] In some examples, the at least one feedback message includes
at least one negative-acknowledgement feedback message, at least
one acknowledgement feedback message, or both.
[0148] In some examples, the unicast transmission manager 745 may
be configured as or otherwise support a means for determining that
no feedback messages were received. In some examples, the unicast
transmission manager 745 may be configured as or otherwise support
a means for increasing, based on the no feedback messages, the
contention window size for performing the one or more subsequent
transmissions.
[0149] In some examples, the unicast transmission manager 745 may
be configured as or otherwise support a means for determining that
at least one acknowledgement feedback message was received. In some
examples, the unicast transmission manager 745 may be configured as
or otherwise support a means for resetting, based on the at least
one acknowledgement feedback message, the contention window size
for performing the one or more subsequent transmissions.
[0150] In some examples, the unicast transmission manager 745 may
be configured as or otherwise support a means for determining that
no feedback messages were received or that a
negative-acknowledgement feedback message was received. In some
examples, the unicast transmission manager 745 may be configured as
or otherwise support a means for increasing, based on the no
feedback messages or the negative-acknowledgement feedback message,
the contention window size for performing the one or more
subsequent transmissions.
[0151] In some examples, the connection-based groupcast
transmission manager 750 may be configured as or otherwise support
a means for determining that at least one acknowledgement feedback
message, at least one negative-acknowledgement feedback message, or
both, were received from the one or more receiving devices. In some
examples, the connection-based groupcast transmission manager 750
may be configured as or otherwise support a means for resetting,
based on the at least one acknowledgement feedback message, the at
least one negative-acknowledgement feedback message, or both, the
contention window size for performing the one or more subsequent
transmissions.
[0152] In some examples, the connection-based groupcast
transmission manager 750 may be configured as or otherwise support
a means for applying a weighting factor to one or more
negative-acknowledgement feedback messages received from the one or
more receiving devices, where resetting the contention window size
for performing the one or more subsequent transmissions based on
the weighting factor.
[0153] In some examples, the connection-based groupcast
transmission manager 750 may be configured as or otherwise support
a means for applying a weighting factor to each received
negative-acknowledgement feedback message to obtain a discounted
negative-acknowledgement feedback messages, where determining that
the ratio satisfies the threshold is based on the acknowledgement
feedback message and the discounted negative-acknowledgement
feedback messages.
[0154] In some examples, the connection-based groupcast
transmission manager 750 may be configured as or otherwise support
a means for determining that at least one acknowledgement feedback
message, at least one negative-acknowledgement feedback message, or
both, were received from the one or more receiving devices. In some
examples, the connection-based groupcast transmission manager 750
may be configured as or otherwise support a means for determining
that a ratio of acknowledgement feedback messages,
negative-acknowledgement messages, or both, to an expected feedback
message count satisfies a threshold. In some examples, the
connection-based groupcast transmission manager 750 may be
configured as or otherwise support a means for resetting, based on
the ratio satisfying the threshold, the contention window size for
performing the one or more subsequent transmissions.
[0155] In some examples, the connection-based groupcast
transmission manager 750 may be configured as or otherwise support
a means for determining that at least one acknowledgement feedback
message, at least one negative-acknowledgement feedback message, or
both, were received from the one or more receiving devices. In some
examples, the connection-based groupcast transmission manager 750
may be configured as or otherwise support a means for determining
that a ratio of acknowledgement feedback messages,
negative-acknowledgement messages, or both, to an expected feedback
message count fails to satisfy a threshold. In some examples, the
connection-based groupcast transmission manager 750 may be
configured as or otherwise support a means for increasing, based on
the ratio failing to satisfy the threshold, the contention window
size for performing the one or more subsequent transmissions.
[0156] In some examples, the connection-based groupcast
transmission manager 750 may be configured as or otherwise support
a means for applying a weighting factor to each received
negative-acknowledgement feedback message to obtain a discounted
negative-acknowledgement feedback messages, where determining that
the ratio satisfies the threshold is based on the acknowledgement
feedback message and the discounted negative-acknowledgement
feedback messages.
[0157] In some examples, the connection-based groupcast
transmission manager 750 may be configured as or otherwise support
a means for determining that at least one acknowledgement feedback
message was received from the one or more receiving devices. In
some examples, the connection-based groupcast transmission manager
750 may be configured as or otherwise support a means for
resetting, based on the at least one acknowledgement feedback
message, the contention window size for performing the one or more
subsequent transmissions.
[0158] In some examples, the connection-based groupcast
transmission manager 750 may be configured as or otherwise support
a means for determining that no acknowledgement feedback messages
were received from the one or more receiving devices. In some
examples, the 755 may be configured as or otherwise support a means
for increasing, based on no acknowledgement feedback messages, the
contention window size for performing the one or more subsequent
transmissions.
[0159] In some examples, the mixed transmission type 760 may be
configured as or otherwise support a means for determining, for one
or more transmission types of the mixed transmission types, that at
least one acknowledgement feedback message was received from the
one or more receiving devices. In some examples, the mixed
transmission type 760 may be configured as or otherwise support a
means for applying, based on the transmission type of the mixed
transmission type, a weighting factor to each acknowledgement
feedback message to obtain a weighted acknowledgement metric. In
some examples, the mixed transmission type 760 may be configured as
or otherwise support a means for resetting, based on the weighted
acknowledgement metric satisfying a threshold, the contention
window size for performing the one or more subsequent
transmissions.
[0160] In some examples, each transmission type of the mixed
transmission type is associated with a same weighting factor or
with different weighting factors.
[0161] In some examples, the mixed transmission type include a
unicast transmission type, a connection-based groupcast
transmission type, a connectionless-based groupcast transmission
type, or a combination thereof.
[0162] In some examples, the mixed transmission type 760 may be
configured as or otherwise support a means for determining that no
feedback messages were received from the one or more receiving
devices. In some examples, the mixed transmission type 760 may be
configured as or otherwise support a means for maintaining, based
on the no feedback messages, the contention window size for
performing the one or more subsequent transmissions.
[0163] In some examples, the mixed transmission type include a
unicast transmission type, a connection-based groupcast
transmission type, a connectionless-based groupcast transmission
type, or a combination thereof.
[0164] FIG. 8 shows a diagram of a system 800 including a device
805 that supports contention window adjustment for new radio
unlicensed/sidelink in accordance with aspects of the present
disclosure. The device 805 may be an example of or include the
components of a device 505, a device 605, or a UE 115 as described
herein. The device 805 may communicate wirelessly with one or more
base stations 105, UEs 115, or any combination thereof. The device
805 may include components for bi-directional voice and data
communications including components for transmitting and receiving
communications, such as a communications manager 820, an
input/output (I/O) controller 810, a transceiver 815, an antenna
825, a memory 830, code 835, and a processor 840. These components
may be in electronic communication or otherwise coupled (e.g.,
operatively, communicatively, functionally, electronically,
electrically) via one or more buses (e.g., a bus 845).
[0165] The I/O controller 810 may manage input and output signals
for the device 805. The I/O controller 810 may also manage
peripherals not integrated into the device 805. In some cases, the
I/O controller 810 may represent a physical connection or port to
an external peripheral. In some cases, the I/O controller 810 may
utilize an operating system such as iOS.RTM., ANDROID.RTM.,
MS-DOS.RTM., MS-WINDOWS.RTM., OS/2.RTM., UNIX.RTM., LINUX.RTM., or
another known operating system. Additionally, or alternatively, the
I/O controller 810 may represent or interact with a modem, a
keyboard, a mouse, a touchscreen, or a similar device. In some
cases, the I/O controller 810 may be implemented as part of a
processor, such as the processor 840. In some cases, a user may
interact with the device 805 via the I/O controller 810 or via
hardware components controlled by the I/O controller 810.
[0166] In some cases, the device 805 may include a single antenna
825. However, in some other cases, the device 805 may have more
than one antenna 825, which may be capable of concurrently
transmitting or receiving multiple wireless transmissions. The
transceiver 815 may communicate bi-directionally, via the one or
more antennas 825, wired, or wireless links as described herein.
For example, the transceiver 815 may represent a wireless
transceiver and may communicate bi-directionally with another
wireless transceiver. The transceiver 815 may also include a modem
to modulate the packets, to provide the modulated packets to one or
more antennas 825 for transmission, and to demodulate packets
received from the one or more antennas 825. The transceiver 815, or
the transceiver 815 and one or more antennas 825, may be an example
of a transmitter 515, a transmitter 615, a receiver 510, a receiver
610, or any combination thereof or component thereof, as described
herein.
[0167] The memory 830 may include random access memory (RAM) and
read-only memory (ROM). The memory 830 may store computer-readable,
computer-executable code 835 including instructions that, when
executed by the processor 840, cause the device 805 to perform
various functions described herein. The code 835 may be stored in a
non-transitory computer-readable medium such as system memory or
another type of memory. In some cases, the code 835 may not be
directly executable by the processor 840 but may cause a computer
(e.g., when compiled and executed) to perform functions described
herein. In some cases, the memory 830 may contain, among other
things, a basic I/O system (BIOS) which may control basic hardware
or software operation such as the interaction with peripheral
components or devices.
[0168] The processor 840 may include an intelligent hardware device
(e.g., a general-purpose processor, a DSP, a CPU, a
microcontroller, an ASIC, an FPGA, a programmable logic device, a
discrete gate or transistor logic component, a discrete hardware
component, or any combination thereof). In some cases, the
processor 840 may be configured to operate a memory array using a
memory controller. In some other cases, a memory controller may be
integrated into the processor 840. The processor 840 may be
configured to execute computer-readable instructions stored in a
memory (e.g., the memory 830) to cause the device 805 to perform
various functions (e.g., functions or tasks supporting contention
window adjustment for new radio unlicensed/sidelink). For example,
the device 805 or a component of the device 805 may include a
processor 840 and memory 830 coupled to the processor 840, the
processor 840 and memory 830 configured to perform various
functions described herein.
[0169] The communications manager 820 may support wireless
communication at a transmitting device in accordance with examples
as disclosed herein. For example, the communications manager 820
may be configured as or otherwise support a means for performing a
first transmission to one or more receiving devices, the first
transmission associated with a transmission type. The
communications manager 820 may be configured as or otherwise
support a means for determining a feedback response for the first
transmission based on monitoring for feedback messages from the one
or more receiving devices in response to the first transmission.
The communications manager 820 may be configured as or otherwise
support a means for selecting a contention window size for
performing one or more subsequent transmissions based on the
feedback response and the transmission type. The communications
manager 820 may be configured as or otherwise support a means for
performing the one or more subsequent transmissions in accordance
with a clear channel assessment procedure using the selected
contention window size.
[0170] By including or configuring the communications manager 820
in accordance with examples as described herein, the device 805 may
support techniques for improving contention window size updates for
CCA procedures performed on a sidelink channel based on the
feedback response for a transmission and the corresponding
transmission type of that transmission.
[0171] In some examples, the communications manager 820 may be
configured to perform various operations (e.g., receiving,
monitoring, transmitting) using or otherwise in cooperation with
the transceiver 815, the one or more antennas 825, or any
combination thereof. Although the communications manager 820 is
illustrated as a separate component, in some examples, one or more
functions described with reference to the communications manager
820 may be supported by or performed by the processor 840, the
memory 830, the code 835, or any combination thereof. For example,
the code 835 may include instructions executable by the processor
840 to cause the device 805 to perform various aspects of
contention window adjustment for new radio unlicensed/sidelink as
described herein, or the processor 840 and the memory 830 may be
otherwise configured to perform or support such operations.
[0172] FIG. 9 shows a diagram of a system 900 including a device
905 that supports contention window adjustment for new radio
unlicensed/sidelink in accordance with aspects of the present
disclosure. The device 905 may be an example of or include the
components of a device 505, a device 605, or a base station 105 as
described herein. The device 905 may communicate wirelessly with
one or more base stations 105, UEs 115, or any combination thereof.
The device 905 may include components for bi-directional voice and
data communications including components for transmitting and
receiving communications, such as a communications manager 920, a
network communications manager 910, a transceiver 915, an antenna
925, a memory 930, code 935, a processor 940, and an inter-station
communications manager 945. These components may be in electronic
communication or otherwise coupled (e.g., operatively,
communicatively, functionally, electronically, electrically) via
one or more buses (e.g., a bus 950).
[0173] The network communications manager 910 may manage
communications with a core network 130 (e.g., via one or more wired
backhaul links). For example, the network communications manager
910 may manage the transfer of data communications for client
devices, such as one or more UEs 115.
[0174] In some cases, the device 905 may include a single antenna
925. However, in some other cases the device 905 may have more than
one antenna 925, which may be capable of concurrently transmitting
or receiving multiple wireless transmissions. The transceiver 915
may communicate bi-directionally, via the one or more antennas 925,
wired, or wireless links as described herein. For example, the
transceiver 915 may represent a wireless transceiver and may
communicate bi-directionally with another wireless transceiver. The
transceiver 915 may also include a modem to modulate the packets,
to provide the modulated packets to one or more antennas 925 for
transmission, and to demodulate packets received from the one or
more antennas 925. The transceiver 915, or the transceiver 915 and
one or more antennas 925, may be an example of a transmitter 515, a
transmitter 615, a receiver 510, a receiver 610, or any combination
thereof or component thereof, as described herein.
[0175] The memory 930 may include RAM and ROM. The memory 930 may
store computer-readable, computer-executable code 935 including
instructions that, when executed by the processor 940, cause the
device 905 to perform various functions described herein. The code
935 may be stored in a non-transitory computer-readable medium such
as system memory or another type of memory. In some cases, the code
935 may not be directly executable by the processor 940 but may
cause a computer (e.g., when compiled and executed) to perform
functions described herein. In some cases, the memory 930 may
contain, among other things, a BIOS which may control basic
hardware or software operation such as the interaction with
peripheral components or devices.
[0176] The processor 940 may include an intelligent hardware device
(e.g., a general-purpose processor, a DSP, a CPU, a
microcontroller, an ASIC, an FPGA, a programmable logic device, a
discrete gate or transistor logic component, a discrete hardware
component, or any combination thereof). In some cases, the
processor 940 may be configured to operate a memory array using a
memory controller. In some other cases, a memory controller may be
integrated into the processor 940. The processor 940 may be
configured to execute computer-readable instructions stored in a
memory (e.g., the memory 930) to cause the device 905 to perform
various functions (e.g., functions or tasks supporting contention
window adjustment for new radio unlicensed/sidelink). For example,
the device 905 or a component of the device 905 may include a
processor 940 and memory 930 coupled to the processor 940, the
processor 940 and memory 930 configured to perform various
functions described herein.
[0177] The inter-station communications manager 945 may manage
communications with other base stations 105, and may include a
controller or scheduler for controlling communications with UEs 115
in cooperation with other base stations 105. For example, the
inter-station communications manager 945 may coordinate scheduling
for transmissions to UEs 115 for various interference mitigation
techniques such as beamforming or joint transmission. In some
examples, the inter-station communications manager 945 may provide
an X2 interface within an LTE/LTE-A wireless communications network
technology to provide communication between base stations 105.
[0178] The communications manager 920 may support wireless
communication at a transmitting device in accordance with examples
as disclosed herein. For example, the communications manager 920
may be configured as or otherwise support a means for performing a
first transmission to one or more receiving devices, the first
transmission associated with a transmission type. The
communications manager 920 may be configured as or otherwise
support a means for determining a feedback response for the first
transmission based on monitoring for feedback messages from the one
or more receiving devices in response to the first transmission.
The communications manager 920 may be configured as or otherwise
support a means for selecting a contention window size for
performing one or more subsequent transmissions based on the
feedback response and the transmission type. The communications
manager 920 may be configured as or otherwise support a means for
performing the one or more subsequent transmissions in accordance
with a clear channel assessment procedure using the selected
contention window size.
[0179] By including or configuring the communications manager 920
in accordance with examples as described herein, the device 905 may
support techniques for improving contention window size updates for
CCA procedures performed on a sidelink channel based on the
feedback response for a transmission and the corresponding
transmission type of that transmission.
[0180] In some examples, the communications manager 920 may be
configured to perform various operations (e.g., receiving,
monitoring, transmitting) using or otherwise in cooperation with
the transceiver 915, the one or more antennas 925, or any
combination thereof. Although the communications manager 920 is
illustrated as a separate component, in some examples, one or more
functions described with reference to the communications manager
920 may be supported by or performed by the processor 940, the
memory 930, the code 935, or any combination thereof. For example,
the code 935 may include instructions executable by the processor
940 to cause the device 905 to perform various aspects of
contention window adjustment for new radio unlicensed/sidelink as
described herein, or the processor 940 and the memory 930 may be
otherwise configured to perform or support such operations.
[0181] FIG. 10 shows a flowchart illustrating a method 1000 that
supports contention window adjustment for new radio
unlicensed/sidelink in accordance with aspects of the present
disclosure. The operations of the method 1000 may be implemented by
a UE or a base station or its components as described herein. For
example, the operations of the method 1000 may be performed by a UE
115 or a base station 105 as described with reference to FIGS. 1
through 9. In some examples, a UE or a base station may execute a
set of instructions to control the functional elements of the UE or
the base station to perform the described functions. Additionally,
or alternatively, the UE or the base station may perform aspects of
the described functions using special-purpose hardware.
[0182] At 1005, the method may include performing a first
transmission to one or more receiving devices, the first
transmission associated with a transmission type. The operations of
1005 may be performed in accordance with examples as disclosed
herein. In some examples, aspects of the operations of 1005 may be
performed by a transmission manager 725 as described with reference
to FIG. 7.
[0183] At 1010, the method may include determining a feedback
response for the first transmission based on monitoring for
feedback messages from the one or more receiving devices in
response to the first transmission. The operations of 1010 may be
performed in accordance with examples as disclosed herein. In some
examples, aspects of the operations of 1010 may be performed by a
feedback response manager 730 as described with reference to FIG.
7.
[0184] At 1015, the method may include selecting a contention
window size for performing one or more subsequent transmissions
based on the feedback response and the transmission type. The
operations of 1015 may be performed in accordance with examples as
disclosed herein. In some examples, aspects of the operations of
1015 may be performed by a contention window size 735 as described
with reference to FIG. 7.
[0185] At 1020, the method may include performing the one or more
subsequent transmissions in accordance with a clear channel
assessment procedure using the selected contention window size. The
operations of 1020 may be performed in accordance with examples as
disclosed herein. In some examples, aspects of the operations of
1020 may be performed by a transmission manager 725 as described
with reference to FIG. 7.
[0186] FIG. 11 shows a flowchart illustrating a method 1100 that
supports contention window adjustment for new radio
unlicensed/sidelink in accordance with aspects of the present
disclosure. The operations of the method 1100 may be implemented by
a UE or a base station or its components as described herein. For
example, the operations of the method 1100 may be performed by a UE
115 or a base station 105 as described with reference to FIGS. 1
through 9. In some examples, a UE or a base station may execute a
set of instructions to control the functional elements of the UE or
the base station to perform the described functions. Additionally,
or alternatively, the UE or the base station may perform aspects of
the described functions using special-purpose hardware.
[0187] At 1105, the method may include performing a first
transmission to one or more receiving devices, the first
transmission associated with a transmission type. The operations of
1105 may be performed in accordance with examples as disclosed
herein. In some examples, aspects of the operations of 1105 may be
performed by a transmission manager 725 as described with reference
to FIG. 7.
[0188] At 1110, the method may include determining a feedback
response for the first transmission based on monitoring for
feedback messages from the one or more receiving devices in
response to the first transmission. The operations of 1110 may be
performed in accordance with examples as disclosed herein. In some
examples, aspects of the operations of 1110 may be performed by a
feedback response manager 730 as described with reference to FIG.
7.
[0189] At 1115, the method may include selecting a contention
window size for performing one or more subsequent transmissions
based on the feedback response and the transmission type. The
operations of 1115 may be performed in accordance with examples as
disclosed herein. In some examples, aspects of the operations of
1115 may be performed by a contention window size 735 as described
with reference to FIG. 7.
[0190] At 1120, the method may include performing the one or more
subsequent transmissions in accordance with a clear channel
assessment procedure using the selected contention window size. The
operations of 1120 may be performed in accordance with examples as
disclosed herein. In some examples, aspects of the operations of
1120 may be performed by a transmission manager 725 as described
with reference to FIG. 7.
[0191] At 1125, the method may include determining that no feedback
messages were received from the one or more receiving devices for
the first transmission. The operations of 1125 may be performed in
accordance with examples as disclosed herein. In some examples,
aspects of the operations of 1125 may be performed by a
connectionless groupcast transmission manager 740 as described with
reference to FIG. 7.
[0192] At 1130, the method may include determining that a second
transmission type was multiplexed with the first transmission
during a same slot, the second transmission associated with a
different transmission type. The operations of 1130 may be
performed in accordance with examples as disclosed herein. In some
examples, aspects of the operations of 1130 may be performed by a
connectionless groupcast transmission manager 740 as described with
reference to FIG. 7.
[0193] At 1135, the method may include selecting, based on
receiving at least one feedback message for the second
transmission, the contention window size for performing the one or
more subsequent transmissions. The operations of 1135 may be
performed in accordance with examples as disclosed herein. In some
examples, aspects of the operations of 1135 may be performed by a
connectionless groupcast transmission manager 740 as described with
reference to FIG. 7.
[0194] FIG. 12 shows a flowchart illustrating a method 1200 that
supports contention window adjustment for new radio
unlicensed/sidelink in accordance with aspects of the present
disclosure. The operations of the method 1200 may be implemented by
a UE or a base station or its components as described herein. For
example, the operations of the method 1200 may be performed by a UE
115 or a base station 105 as described with reference to FIGS. 1
through 9. In some examples, a UE or a base station may execute a
set of instructions to control the functional elements of the UE or
the base station to perform the described functions. Additionally,
or alternatively, the UE or the base station may perform aspects of
the described functions using special-purpose hardware.
[0195] At 1205, the method may include performing a first
transmission to one or more receiving devices, the first
transmission associated with a transmission type. The operations of
1205 may be performed in accordance with examples as disclosed
herein. In some examples, aspects of the operations of 1205 may be
performed by a transmission manager 725 as described with reference
to FIG. 7.
[0196] At 1210, the method may include determining a feedback
response for the first transmission based on monitoring for
feedback messages from the one or more receiving devices in
response to the first transmission. The operations of 1210 may be
performed in accordance with examples as disclosed herein. In some
examples, aspects of the operations of 1210 may be performed by a
feedback response manager 730 as described with reference to FIG.
7.
[0197] At 1215, the method may include selecting a contention
window size for performing one or more subsequent transmissions
based on the feedback response and the transmission type. The
operations of 1215 may be performed in accordance with examples as
disclosed herein. In some examples, aspects of the operations of
1215 may be performed by a contention window size 735 as described
with reference to FIG. 7.
[0198] At 1220, the method may include performing the one or more
subsequent transmissions in accordance with a clear channel
assessment procedure using the selected contention window size. The
operations of 1220 may be performed in accordance with examples as
disclosed herein. In some examples, aspects of the operations of
1220 may be performed by a transmission manager 725 as described
with reference to FIG. 7.
[0199] At 1225, the method may include determining that no feedback
messages were received from the one or more receiving devices. The
operations of 1225 may be performed in accordance with examples as
disclosed herein. In some examples, aspects of the operations of
1225 may be performed by a connectionless groupcast transmission
manager 740 as described with reference to FIG. 7.
[0200] At 1230, the method may include determining that no second
transmission types were multiplexed with the first transmission
during a same slot. The operations of 1230 may be performed in
accordance with examples as disclosed herein. In some examples,
aspects of the operations of 1230 may be performed by a
connectionless groupcast transmission manager 740 as described with
reference to FIG. 7.
[0201] At 1235, the method may include maintaining, based on no
feedback messages and no second transmission types being
multiplexed with the first transmission during the same slot, the
contention window size for performing the one or more subsequent
transmissions. The operations of 1235 may be performed in
accordance with examples as disclosed herein. In some examples,
aspects of the operations of 1235 may be performed by a
connectionless groupcast transmission manager 740 as described with
reference to FIG. 7.
[0202] FIG. 13 shows a flowchart illustrating a method 1300 that
supports contention window adjustment for new radio
unlicensed/sidelink in accordance with aspects of the present
disclosure. The operations of the method 1300 may be implemented by
a UE or a base station or its components as described herein. For
example, the operations of the method 1300 may be performed by a UE
115 or a base station 105 as described with reference to FIGS. 1
through 9. In some examples, a UE or a base station may execute a
set of instructions to control the functional elements of the UE or
the base station to perform the described functions. Additionally,
or alternatively, the UE or the base station may perform aspects of
the described functions using special-purpose hardware.
[0203] At 1305, the method may include performing a first
transmission to one or more receiving devices, the first
transmission associated with a transmission type. The operations of
1305 may be performed in accordance with examples as disclosed
herein. In some examples, aspects of the operations of 1305 may be
performed by a transmission manager 725 as described with reference
to FIG. 7.
[0204] At 1310, the method may include determining a feedback
response for the first transmission based on monitoring for
feedback messages from the one or more receiving devices in
response to the first transmission. The operations of 1310 may be
performed in accordance with examples as disclosed herein. In some
examples, aspects of the operations of 1310 may be performed by a
feedback response manager 730 as described with reference to FIG.
7.
[0205] At 1315, the method may include selecting a contention
window size for performing one or more subsequent transmissions
based on the feedback response and the transmission type. The
operations of 1315 may be performed in accordance with examples as
disclosed herein. In some examples, aspects of the operations of
1315 may be performed by a contention window size 735 as described
with reference to FIG. 7.
[0206] At 1320, the method may include performing the one or more
subsequent transmissions in accordance with a clear channel
assessment procedure using the selected contention window size. The
operations of 1320 may be performed in accordance with examples as
disclosed herein. In some examples, aspects of the operations of
1320 may be performed by a transmission manager 725 as described
with reference to FIG. 7.
[0207] At 1325, the method may include determining that at least
one feedback message was received from the one or more receiving
devices. The operations of 1325 may be performed in accordance with
examples as disclosed herein. In some examples, aspects of the
operations of 1325 may be performed by a unicast transmission
manager 745 as described with reference to FIG. 7.
[0208] At 1330, the method may include resetting, based on the at
least one feedback message, the contention window size for
performing the one or more subsequent transmissions. The operations
of 1330 may be performed in accordance with examples as disclosed
herein. In some examples, aspects of the operations of 1330 may be
performed by a unicast transmission manager 745 as described with
reference to FIG. 7.
[0209] FIG. 14 shows a flowchart illustrating a method 1400 that
supports contention window adjustment for new radio
unlicensed/sidelink in accordance with aspects of the present
disclosure. The operations of the method 1400 may be implemented by
a UE or a base station or its components as described herein. For
example, the operations of the method 1400 may be performed by a UE
115 or a base station 105 as described with reference to FIGS. 1
through 9. In some examples, a UE or a base station may execute a
set of instructions to control the functional elements of the UE or
the base station to perform the described functions. Additionally,
or alternatively, the UE or the base station may perform aspects of
the described functions using special-purpose hardware.
[0210] At 1405, the method may include performing a first
transmission to one or more receiving devices, the first
transmission associated with a transmission type. The operations of
1405 may be performed in accordance with examples as disclosed
herein. In some examples, aspects of the operations of 1405 may be
performed by a transmission manager 725 as described with reference
to FIG. 7.
[0211] At 1410, the method may include determining a feedback
response for the first transmission based on monitoring for
feedback messages from the one or more receiving devices in
response to the first transmission. The operations of 1410 may be
performed in accordance with examples as disclosed herein. In some
examples, aspects of the operations of 1410 may be performed by a
feedback response manager 730 as described with reference to FIG.
7.
[0212] At 1415, the method may include selecting a contention
window size for performing one or more subsequent transmissions
based on the feedback response and the transmission type. The
operations of 1415 may be performed in accordance with examples as
disclosed herein. In some examples, aspects of the operations of
1415 may be performed by a contention window size 735 as described
with reference to FIG. 7.
[0213] At 1420, the method may include performing the one or more
subsequent transmissions in accordance with a clear channel
assessment procedure using the selected contention window size. The
operations of 1420 may be performed in accordance with examples as
disclosed herein. In some examples, aspects of the operations of
1420 may be performed by a transmission manager 725 as described
with reference to FIG. 7.
[0214] At 1425, the method may include determining that no feedback
messages were received from the one or more receiving devices. The
operations of 1425 may be performed in accordance with examples as
disclosed herein. In some examples, aspects of the operations of
1425 may be performed by a unicast transmission manager 745 as
described with reference to FIG. 7.
[0215] At 1430, the method may include increasing, based on the no
feedback messages, the contention window size for performing the
one or more subsequent transmissions. The operations of 1430 may be
performed in accordance with examples as disclosed herein. In some
examples, aspects of the operations of 1430 may be performed by a
unicast transmission manager 745 as described with reference to
FIG. 7.
[0216] The following provides an overview of aspects of the present
disclosure:
[0217] Aspect 1: A method for wireless communication at a
transmitting device, comprising: performing a first transmission to
one or more receiving devices, the first transmission associated
with a transmission type; determining a feedback response for the
first transmission based on monitoring for feedback messages from
the one or more receiving devices in response to the first
transmission; selecting a contention window size for performing one
or more subsequent transmissions based at least in part on the
feedback response and the transmission type; and performing the one
or more subsequent transmissions in accordance with a CCA procedure
using the selected contention window size.
[0218] Aspect 2: The method of aspect 1, wherein the transmission
type comprises a connectionless-based groupcast transmission type,
further comprising: determining that no feedback messages were
received from the one or more receiving devices for the first
transmission; determining that a second transmission was
multiplexed with the first transmission during a same slot, the
second transmission associated with a different transmission type;
and selecting, based at least in part on receiving at least one
feedback message for the second transmission, the contention window
size for performing the one or more subsequent transmissions.
[0219] Aspect 3: The method of any of aspects 1 through 2, wherein
the transmission type comprises a connectionless-based groupcast
transmission type, further comprising: determining that no feedback
messages were received from the one or more receiving devices;
determining that no second transmission types were multiplexed with
the first transmission during a same slot; and maintaining, based
at least in part on no feedback messages and no second transmission
types being multiplexed with the first transmission during the same
slot, the contention window size for performing the one or more
subsequent transmissions.
[0220] Aspect 4: The method of any of aspects 1 through 3, wherein
the transmission type comprises a connectionless-based groupcast
transmission type, further comprising: determining that at least
one NACK feedback message was received from the one or more
receiving devices; and resetting, based at least in part on the at
least one NACK feedback message, the contention window size for
performing the one or more subsequent transmissions.
[0221] Aspect 5: The method of any of aspects 1 through 4, wherein
the transmission type comprises a unicast transmission type,
further comprising: determining that at least one feedback message
was received; and resetting, based at least in part on the at least
one feedback message, the contention window size for performing the
one or more subsequent transmissions.
[0222] Aspect 6: The method of aspect 5, wherein the at least one
feedback message comprises at least one NACK feedback message, at
least one ACK feedback message, or both.
[0223] Aspect 7: The method of any of aspects 1 through 6, wherein
the transmission type comprises a unicast transmission type,
further comprising: determining that no feedback messages were
received; and increasing, based at least in part on the no feedback
messages, the contention window size for performing the one or more
subsequent transmissions.
[0224] Aspect 8: The method of any of aspects 1 through 7, wherein
the transmission type comprises a unicast transmission type,
further comprising: determining that at least one ACK feedback
message was received; and resetting, based at least in part on the
at least one ACK feedback message, the contention window size for
performing the one or more subsequent transmissions.
[0225] Aspect 9: The method of any of aspects 1 through 8, wherein
the transmission type comprises a unicast transmission type,
further comprising: determining that no feedback messages were
received or that a NACK feedback message was received; and
increasing, based at least in part on the no feedback messages or
the NACK feedback message, the contention window size for
performing the one or more subsequent transmissions.
[0226] Aspect 10: The method of any of aspects 1 through 9, wherein
the transmission type comprises a connection-based groupcast
transmission type, further comprising: determining that at least
one ACK feedback message, at least one NACK feedback message, or
both, were received from the one or more receiving devices; and
resetting, based at least in part on the at least one ACK feedback
message, the at least one NACK feedback message, or both, the
contention window size for performing the one or more subsequent
transmissions.
[0227] Aspect 11: The method of aspect 10, further comprising:
applying a weighting factor to one or more NACK feedback messages
received from the one or more receiving devices, wherein resetting
the contention window size for performing the one or more
subsequent transmissions based at least in part on the weighting
factor.
[0228] Aspect 12: The method of any of aspects 1 through 11,
wherein the transmission type comprises a connection-based
groupcast transmission type, further comprising: determining that
at least one ACK feedback message, at least one NACK feedback
message, or both, were received from the one or more receiving
devices; determining that a ratio of ACK feedback messages, NACK
messages, or both, to an expected feedback message count satisfies
a threshold; and resetting, based at least in part on the ratio
satisfying the threshold, the contention window size for performing
the one or more subsequent transmissions.
[0229] Aspect 13: The method of aspect 12, further comprising:
applying a weighting factor to each received NACK feedback message
to obtain a discounted NACK feedback messages, wherein determining
that a ratio satisfies the threshold is based at least in part on
the ACK feedback message and the discounted NACK feedback
messages.
[0230] Aspect 14: The method of any of aspects 1 through 13,
wherein the transmission type comprises a connection-based
groupcast transmission type, further comprising: determining that
at least one ACK feedback message, at least one NACK feedback
message, or both, were received from the one or more receiving
devices; determining that a ratio of ACK feedback messages, NACK
messages, or both, to an expected feedback message count fails to
satisfy a threshold; and increasing, based at least in part on the
ratio failing to satisfy the threshold, the contention window size
for performing the one or more subsequent transmissions.
[0231] Aspect 15: The method of aspect 14, further comprising:
applying a weighting factor to each received NACK feedback message
to obtain a discounted NACK feedback messages, wherein determining
that the ratio satisfies the threshold is based at least in part on
the ACK feedback message and the discounted NACK feedback
messages.
[0232] Aspect 16: The method of any of aspects 1 through 15,
wherein the transmission type comprises a connection-based
groupcast transmission type, further comprising: determining that
at least one ACK feedback message was received from the one or more
receiving devices; and resetting, based at least in part on the at
least one ACK feedback message, the contention window size for
performing the one or more subsequent transmissions.
[0233] Aspect 17: The method of any of aspects 1 through 16,
wherein the transmission type comprises a connection-based
groupcast transmission type, further comprising:
[0234] determining that no ACK feedback messages were received from
the one or more receiving devices; and increasing, based at least
in part on no ACK feedback messages, the contention window size for
performing the one or more subsequent transmissions.
[0235] Aspect 18: The method of any of aspects 1 through 17,
wherein the transmission type comprises a mixed transmission type,
further comprising: determining, for one or more transmission types
of the mixed transmission types, that at least one ACK feedback
message was received from the one or more receiving devices;
applying, based at least in part on the transmission type of the
mixed transmission type, a weighting factor to each ACK feedback
message to obtain a weighted ACK metric; and resetting, based at
least in part on the weighted ACK metric satisfying a threshold,
the contention window size for performing the one or more
subsequent transmissions.
[0236] Aspect 19: The method of aspect 18, wherein each
transmission type of the mixed transmission type is associated with
a same weighting factor or with different weighting factors.
[0237] Aspect 20: The method of any of aspects 18 through 19,
wherein the mixed transmission type comprise a unicast transmission
type, a connection-based groupcast transmission type, a
connectionless-based groupcast transmission type, or a combination
thereof.
[0238] Aspect 21: The method of any of aspects 1 through 20,
wherein the transmission type comprises a mixed transmission type,
further comprising: determining that no feedback messages were
received from the one or more receiving devices; and maintaining,
based at least in part on the no feedback messages, the contention
window size for performing the one or more subsequent
transmissions.
[0239] Aspect 22: The method of aspect 21, wherein the mixed
transmission type comprise a unicast transmission type, a
connection-based groupcast transmission type, a
connectionless-based groupcast transmission type, or a combination
thereof.
[0240] Aspect 23: An apparatus for wireless communication at a
transmitting device, comprising a processor; memory coupled with
the processor; and instructions stored in the memory and executable
by the processor to cause the apparatus to perform a method of any
of aspects 1 through 22.
[0241] Aspect 24: An apparatus for wireless communication at a
transmitting device, comprising at least one means for performing a
method of any of aspects 1 through 22.
[0242] Aspect 25: A non-transitory computer-readable medium storing
code for wireless communication at a transmitting device, the code
comprising instructions executable by a processor to perform a
method of any of aspects 1 through 22.
[0243] It should be noted that the methods described herein
describe possible implementations, and that the operations and the
steps may be rearranged or otherwise modified and that other
implementations are possible. Further, aspects from two or more of
the methods may be combined.
[0244] Although aspects of an LTE, LTE-A, LTE-A Pro, or NR system
may be described for purposes of example, and LTE, LTE-A, LTE-A
Pro, or NR terminology may be used in much of the description, the
techniques described herein are applicable beyond LTE, LTE-A, LTE-A
Pro, or NR networks. For example, the described techniques may be
applicable to various other wireless communication systems such as
Ultra Mobile Broadband (UMB), Institute of Electrical and
Electronics Engineers (IEEE) 802.11 (Wi-Fi), IEEE 802.16 (WiMAX),
IEEE 802.20, Flash-OFDM, as well as other systems and radio
technologies not explicitly mentioned herein.
[0245] Information and signals described herein may be represented
using any of a variety of different technologies and techniques.
For example, data, instructions, commands, information, signals,
bits, symbols, and chips that may be referenced throughout the
description may be represented by voltages, currents,
electromagnetic waves, magnetic fields or particles, optical fields
or particles, or any combination thereof.
[0246] The various illustrative blocks and components described in
connection with the disclosure herein may be implemented or
performed with a general-purpose processor, a DSP, an ASIC, a CPU,
an FPGA or other programmable logic device, discrete gate or
transistor logic, discrete hardware components, or any combination
thereof designed to perform the functions described herein. A
general-purpose processor may be a microprocessor, but in the
alternative, the processor may be any processor, controller,
microcontroller, or state machine. A processor may also be
implemented as a combination of computing devices (e.g., a
combination of a DSP and a microprocessor, multiple
microprocessors, one or more microprocessors in conjunction with a
DSP core, or any other such configuration).
[0247] The functions described herein may be implemented in
hardware, software executed by a processor, firmware, or any
combination thereof. If implemented in software executed by a
processor, the functions may be stored on or transmitted over as
one or more instructions or code on a computer-readable medium.
Other examples and implementations are within the scope of the
disclosure and appended claims. For example, due to the nature of
software, functions described herein may be implemented using
software executed by a processor, hardware, firmware, hardwiring,
or combinations of any of these. Features implementing functions
may also be physically located at various positions, including
being distributed such that portions of functions are implemented
at different physical locations.
[0248] Computer-readable media includes both non-transitory
computer storage media and communication media including any medium
that facilitates transfer of a computer program from one place to
another. A non-transitory storage medium may be any available
medium that may be accessed by a general-purpose or special-purpose
computer. By way of example, and not limitation, non-transitory
computer-readable media may include RAM, ROM, electrically erasable
programmable ROM (EEPROM), flash memory, compact disk (CD) ROM or
other optical disk storage, magnetic disk storage or other magnetic
storage devices, or any other non-transitory medium that may be
used to carry or store desired program code means in the form of
instructions or data structures and that may be accessed by a
general-purpose or special-purpose computer, or a general-purpose
or special-purpose processor. Also, any connection is properly
termed a computer-readable medium. For example, if the software is
transmitted from a website, server, or other remote source using a
coaxial cable, fiber optic cable, twisted pair, digital subscriber
line (DSL), or wireless technologies such as infrared, radio, and
microwave, then the coaxial cable, fiber optic cable, twisted pair,
DSL, or wireless technologies such as infrared, radio, and
microwave are included in the definition of computer-readable
medium. Disk and disc, as used herein, include CD, laser disc,
optical disc, digital versatile disc (DVD), floppy disk and Blu-ray
disc where disks usually reproduce data magnetically, while discs
reproduce data optically with lasers. Combinations of the above are
also included within the scope of computer-readable media.
[0249] As used herein, including in the claims, "or" as used in a
list of items (e.g., a list of items prefaced by a phrase such as
"at least one of" or "one or more of") indicates an inclusive list
such that, for example, a list of at least one of A, B, or C means
A or B or C or AB or AC or BC or ABC (i.e., A and B and C). Also,
as used herein, the phrase "based on" shall not be construed as a
reference to a closed set of conditions. For example, an example
step that is described as "based on condition A" may be based on
both a condition A and a condition B without departing from the
scope of the present disclosure. In other words, as used herein,
the phrase "based on" shall be construed in the same manner as the
phrase "based at least in part on."
[0250] In the appended figures, similar components or features may
have the same reference label. Further, various components of the
same type may be distinguished by following the reference label by
a dash and a second label that distinguishes among the similar
components. If just the first reference label is used in the
specification, the description is applicable to any one of the
similar components having the same first reference label
irrespective of the second reference label, or other subsequent
reference label.
[0251] The description set forth herein, in connection with the
appended drawings, describes example configurations and does not
represent all the examples that may be implemented or that are
within the scope of the claims. The term "example" used herein
means "serving as an example, instance, or illustration," and not
"preferred" or "advantageous over other examples." The detailed
description includes specific details for the purpose of providing
an understanding of the described techniques. These techniques,
however, may be practiced without these specific details. In some
instances, known structures and devices are shown in block diagram
form in order to avoid obscuring the concepts of the described
examples.
[0252] The description herein is provided to enable a person having
ordinary skill in the art to make or use the disclosure. Various
modifications to the disclosure will be apparent to a person having
ordinary skill in the art, and the generic principles defined
herein may be applied to other variations without departing from
the scope of the disclosure. Thus, the disclosure is not limited to
the examples and designs described herein but is to be accorded the
broadest scope consistent with the principles and novel features
disclosed herein.
* * * * *